Sony PS-4750
Superb Fidelity from Today’s Most Advanced Direct Drive
Audio experts the world over have been waiting
for it Sony’s incredible PS 4750, the ultimate
turntable system.
the art takes on a new meaning with the
PS 4750, probably the quietest turntable ever
made.
In one elegant design Sony has reduced rumble
feedback wow and flutter to minute levels far ’
beyond hearing and virtually beyond measurement.
Wow and flutter for instance is an amazing 0.03%
(wrms.) Signal to noise is better than 70 dB (DIN-B).
Sony achieved this in a number of ways:
First, all the belts, pulleys, idler wheels and other
paraphernalia used in conventional turntables to
make the turntable spin at the record’s speed
instead of the motor’s, have been eliminated. ’
The Sony PS 4750 has no need for these trouble¬
some, noisy and fluttering parts, because its
slow-revving D.C. motor is directly coupled to the
pialtGr.
Speed accuracy takes on new meaning with
another Sony breakthrough, the “Magne-disc
Servo Control.” a
Through a unique multi-gap head, this system
automatically reads turntable speed through speed
rim !hV® M9*Kals ™a9net-coated on to the turntable
rim Should there be any deviation induced by
fluctuations in power supply, jt immediately
instructs the servo motor to make micro-
accurate adjustments.
Another triumph of Sony research is the very
d use<^ make the cabinet and turntable
developed specifically for audio use
because its damping and resonance characteristics
are 30 per cent better than the conventional
aluminium diecast. B.M.C. is also virtually free of
expansion or contraction, freeing the design of
any problems ar sing from temperature changes.
Sony innovation didn’t stop there. Look at the
revolutionary rubber disc supports. These insulation
mats are of a unique design which firmly grips the
record effectively insulating the disc from vibration
when the turntable revolves. By preventing
vibrations, these mats contribute to the stereo
effect and significantly improve presence.
The precision tonearm is a universal type which
accepts all quality shells and cartridges. Some of
the Sony PS 4750's other advanced features are-
stylus pressure adjustment (0-3 g), anti-skate
compensator, viscous-damped (up and down) arm
S,e,elth!EU9h stroboscope, independent pitch
control ( + 4 /£> on both 331/3 and 45) and large
feedback 908 ^ effective Prevention of audio
If you’ve been waiting for the ultimate turntable
drive^l 475a0 is°herr‘ ^ S°ny direCt''
®
Research Makes the Difference
GAC.S 7532
Australia's largest-selling electronics & hi-fi magazine
VOLUME 38 No 9
*
^£a)_ modular digital clock
This is our latest digital clock, a versatile
new design that's simple to build and easy
to get going. The design offers several
options, and can be expanded to include
alarm, snooze, sleep and radio switching
functions. We give you all the details in
our article commencing on page 52.
Next month:
Microcomputers are now quite low in
cost, but to use them you need a low
cost terminal. Next month in EA we will
present a new design for a low cost
build it yourself video terminal, using
any monochrome or colour TV set.
Among its many attractive features
are:
• Refresh memory of 1024
characters
• Three different display formats
• Crystal controlled, no setting up
• Serial interface at any of nine crystal-
locked baud rates
• Both video and RF outputs
• Roll up and roll down facility.
All this at a price well below that of
competitive terminals!
Don't miss our January issue for this
trend-setting new project.
On the cover
Our cover picture this month shows the
latest Siemens teleprinter unit, locally
made at the Siemens plant in Richmond,
Victoria. Some 25,000 Siemens teleprin¬
ters are now linked into the Australian
telex and telegraph networks. (Photo
courtesy Siemens Industries).
CONTENTS— DECEMBER, 1976
world of electronics and hi-fi
3 Editorial: A threat or a challenge?
9 Hi-Fi News:
AIWA wants some of the hi-fi action— Goldring doings things in sty/i
Miniature mic. for home moviemakers— CENTREX: Quality sound on the
move—Bogen / Tech craft now handled by Audio Telex
1 7 New AWA monitor uses duplex woofers— unique Australian design
20 Microphones Pt 3: Frequency response, directivity, etc.
23 Review: New electret microphones and accessories from JVC
25 Review: Luxor 9341 automatic turntable
27 Review: Magnetic cartridges from National Panasonic
30 Light beam communication in the 1 980s— the optical fibre revolution
37 Australia's first domestic cable TV system
38 AC bridge circuit for precise temperature measurements
66 Forum: Is 2-channel stereo the pure system?
projects and technical
40 Playmaster Forty/ Forty stereo amplifier
48 Easy-to-build, low cost telephone amplifier for beginners
52 Modular digital clock— versatile new design offers several options
59 Auto rhythm unit for electronic organs— using the S8890 rhythm chip
62 Op-amps without tears— a practical, down-to-earth introduction to op-amps
70 A direct conversion receiver for 3.5MHz
78 The serviceman: Handyman successes— and failures
83 Circuit and design ideas:
Designing optimum-Q and small inductors— Shunt stabilised power
supply— TTL counter divides by any integer— Double-pole battery time
switch
86 Getting into microprocessors: The Mostek F8
89 Getting into microprocessors: The Sphere system
90 Getting into microprocessors: SC/MP gets Tiny-BASIC
92 Getting into microprocessors: A text editor for SC/MP
104 Introduction to digital electronics— 1 1 : Encoding and decoding
114 New products:
New Nipper 48 colour TV performs well— Infra-red intruder alarm—
Wideband preamp for instruments— Video Technics TV tuner— Puncture
tester— AudioLarms form C&K—CB dealers wanted— Video game— Edge
connectors— Paper tape punch— New calculators from Unitrex.
regular features
32 News highlights
95 Record reviews— classical
99 Record reviews— devotional, popular, jazz
1 1 2 Book reviews
1 23 Letters to the Editor
125 The amateur bands
1 29 Shortwave scene
131 Information centre
1 34 Marketplace— classified
1 36 Index to advertisers
133 Notes and errata
ELECTRONICS Australia, December, 1976
1
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Total harmonic distortion less than .4%
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CSV 50 — 25 Watts urns per Channel Stereo Amplifier
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GV30
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$28.83
CSV222 STEREO AMPLIFIER
2
ELECTRONICS Australia. December. 1976
Editorial
Viewpoint
A threat or a challenge?
EDITOR-IN-CHIEF
Neville Williams
M.I.R.E.E. (Aust.) (VK2XV)
EDITOR
Jamieson Rowe
B.A. (Sydney), B.Sc. (Technology, NSW)
M.I.R.E.E. (Aust.) (VK2ZL0/T)
ASSISTANT EDITOR
Philip Watson
A. M.I.R.E.E. (Aust.) (VK2ZPW)
SCIENCE FEATURES
Greg Swain, B.Sc. (Hons, Sydney)
PRODUCT REVIEWS
Leo Simpson
TECHNICAL PROJECTS
David Edwards, B E. (Hons, Tasmania)
Ian Pogson (VK2AZN/T)
GRAPHICS
Robert Flynn
PRODUCTION
Daniel Hooper
ADVERTISING MANAGER
Selwyn Sayers
CIRCULATION MANAGER
Alan Parker
Broadly speaking, I think most people in electronics— whether hobbyist or
professional— are fairly excited about microprocessors. This is probably because we
are able to recognise that they are in fact a dual development.
We can certainly see that they are a further step in the evolution of conventional
computers, a step which is lowering costs and thus bringing computing power right
down into the mainstream of everyday life. But at the same time we can also see
that they are a logical development of large-scale integration technology, a develop¬
ment which will probably broaden the range of dedicated electronic controls and
systems a thousandfold.
It is this second aspect of microprocessors which is mainly responsible for the
current revolution in electronics, not the first. If the only benefit of microprocessors
was cheaper and more accessible "number crunchers", they would'nt be making
the impact they are. And we in electronics wouldn't be in the midst of planning
for an exciting new era.
Why I mention all this again is that I have been intrigued lately by the attitudes
and reactions towards microprocessors displayed by many people in the existing
computer industry. Both from talking to them, and from reading industry publications,
I have the impression that quite a few computer professionals are either apathetic
or patronisingly disdainful.
At first I found these reactions rather puzzling, but now I think I understand.
For the last 15 or 20 years, computer professionals have been able to establish
themselves comfortably as an indispensable elite: a white-coated priestly caste,
whose mysterious ministrations were deemed essential if computers were to perform
anything useful. The arrival of minicomputers tended to weaken this elite image a
little, as they proved capable of being driven effectively by mere electronics engineers
and technicians. But by and large, any computer facility worthy of the name still
needed its retinue of systems analysts, programmers and other assorted boffins.
Then along came these horrid little microprocessors, with their obvious implica¬
tions of low cost computing facilities within reach of almost anyone— even hobByists
and school students!
It's understandable, then, that some computer people aren't nearly as keen about
microprocessors as we in electronics tend to be; the new devices are seen as a threat
to their future status and well-being.
Of course the truth is that computer folk and their accumulated experience are
going to be invaluable as we enter this new phase of computing and electronics.
They may have to change a little, and accept a less mystic image. But on the other
hand we in electronics are having to change too-and among other things, we are
having to learn basic programming!
If we work together, I think the future should be very rewarding for us all— and
for humankind.
That optimistic note seems to lead on to my final thought, which is not about
microprocessors at all. On behalf of all of us here at EA, I wish you a very merry
Christmas, and a happy and prosperous new year.
— Jamieson Rowe
ON SALE THE FIRST MONDAY OF EACH MONTH
Registered for posting -as a periodical —
Category B.
Printed by Dalley-Middleton-Moore Pty Ltd, of
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'Recommended and maximum price only.
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Sydney— 57-59 Regent St, Sydney 2008.
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Western Australia by Sungravure Pty Ltd, 454
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Copyright. All rights reserved
Devices or arrangements shown or described
herein may embody patents. Information is
furnished without responsibility for its use and
without prejudice to patent rights.
All manuscripts, photographs and other
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ELECTRONICS Australia, December, 1976
3
Dokorder.
A superb range that has sound quality taped*
Increasingly advanced recording techniques mean
that near perfect sound is available to the music
lover. To fully appreciate this sound, you need
equally sophisticated reproduction equipment.
And that’s what Dokorder is all about!
A range of highly sophisticated tape recorders and
decks . . . seven models to select from. One for
every need and budget. For instance, the new 1 1 40
. ... Dokorder’s finest professional
tape deck. Studio quality and a host
of features. And the 81 40 4-channel
tape deck with multi-sync, for fun, flexibility and
fine sound. Then, there’s the new MK550 stereo
cassette deck featuring servo controlled drive
system, built-in Dolby, Cue and Review system,
Peak Level Indicators, Normal/Chrome equaliza¬
tion and a switched FM multiplex filter-features
you should insist on in any first-class deck.
With Dokorder, there certainly is a unit to suit
every need! And every
Dokorder gives you superb
sound quality.
Dokorder.
PHOTIMPOItT
MELBOURNE ADELAIDE BRISBANE PERTH SYDNEY
For descriptive literature and specifications, send a 30 cent stamp
to Qualitron Industries Division of Photimport (Australia) Pty. Ltd.
Head Office: 69 Nicholson Street, East Brunswick, Vic. 3057
Australia. Telephone: 38Q 6922
PA11D’
4
ELECTRONICS Australia, December, 1976
Peerless PMB6-remarkable realism
equal to the best electrostatics
New Peerless Orthodynamic principle -
this is really living
With Peerless PMB6 headphones everything you hear is true.
Based on the newly developed and patented Peerless Ortho¬
dynamic principle, PMB6 headphones deliver reproduced sounds
equal in quality to the most sophisticated electrostatics. Peerless
bring it back alive-sounds so real, you feel you’re actually there.
In one ear and in the other-
in total comfort
There’s nothing more annoying than headphones that clamp
you in a head-lock.
With Peerless featherweight construction, fine fit and pillow-
soft ear pads, absolute comfort is certain over long time listening.
Until you’ve heard it through Peerless -
you just haven’t heard it!
Between two perforated ferrite magnet discs lies an ultra thin
diaphragm/voice coil. This light and very elastic diaphragm, whose
total surface is put into motion, makes crystal clear high frequency
reproduction possible. Its construction also ensures uniform
phase characteristics and low distortion. The diagram below
details this novel new design.
In your favourite piece of recorded music, you’ll hear notes and
nuances you’d never have believed existed.
1. Air holes. 2. Ball joint suspension. 3. Drive unit. 4. Damping material.
5. Terminals. 6. Cable grip. 7. Ear pads. 8. Terminal. 9. Terminal. 10. Centre
axle. 11. Magnet. 12. Magnet. 13. Diaphragm/voice coil. 14. Hole in magnet.
Peerless PMB6 Technical Data
Frequency: Range 16-20,000 Hz
Impedance: 140 Ohms
Max. Constant Load: 40 dB
Operating Power: 2.5 mW
Distortion: 1%
Rated Input: * ’ 2W (DIN)
Weight: 210 g
Colours: Black, Red and Olive Green
Peerless PMB6 $49
Electrostatic quality, superb comfort and a realistic price
Danish Hi Fi Shop 9, Southern Cross Hotel, Melbourne. Telephone 63 8930 Danish Hi Fi 698 Burke Road, Camberwell, Victoria Telephone 82 4839
convoy Sound 1 Maclean Street, Woolloomooloo, N.S.W. Telephone 357 2444. Convoy Sound 387 George Street, Sydney. Telephone 29 4466
Brisbane Agencies 72 Wickham Street, Fortitude Valley, Queensland. Telephone 221 9944. Danish Hi Fi 308 Walcott Street Mt Lawlev
Western Australia. Telephone 71 0100. '
ELECTRONICS Australia, December, 1976
5
Does your system hunger for one?
Hi fi systems also need the right kind of nourishment. One of the most
effective ways of providing it is featured above: the AKAI AA-1020 AM/FM
Tuner Amplifier.
It puts out 20 effortless watts RMS per channel (both channels driven,
from 20 to 20,000 hz, no more than 0.4% THD into 8 ohms load). It comes
with the kind of facilities that produce the best kind of sound. And at $340t,
the price isn’t likely to turn you off.
But maybe your system hungers for a lot more power, in which case
you should see our more powerful models.
Of course, like all AKAI hi fi equipment distributed by AKAI
Australia, it comes with our Complete Protection Plan*. Which simply
means 12 months full parts and labour warranty on all Tape Equipment,
2 years full parts and labour warranty on all Amplifiers, Turntables and
Speakers and a lifetime warranty on all GX Tape Heads.
So, if your amplifier isn’t all it should be, see your AKAI dealer .
He’ll put your mind at ease.
The AKAI Hi-Fi Professionals are: NEW SOUTH WALES - SYDNEY CITY AND METROPOLITAN. Sydney: Douglas Hi-Fi, 338 George Street; Duty Free Travellers Supplies. 400 Kent Street;
European Electronics. 187 Clarence Street; Insirol Hi Fi. Cnr Put & King Streets; Magnetic Sound Industries, 32 York Street; Jack Stein Audio, 275 Clarence Street. Bankstown: Selsound Hi Fi.Cnr.
North Terrace & Apian Way. Burwood: Electronic Enterprises. 1 1 Burwotnl Road. Edge Electrix, 31 Burwood Road Concord: Sonarta Music Services, 24 (^abarita Road. Cremorne: Photo Art & Sound.
287 Military Road Crows Nest: Allied Hi Fi. 330 Pacific Highwjv Hurstville: Hi F: House. 127 Forest Road Liverpool: Miranda Stereo & Hi Fi Centre, 166 Macquarie Street . Miranda Fair: Miranda Hi
Fi & Stereo Centre. Shop 67, Top Level. Mona Vale: Warringah Hi Fi. Shop 5. Mona Vale Court Parramatta: Gramophone Shop. Shop 151 , Westfield Shoppingtown; Selsound Hi Fi, 27 Darcey Street
Roselands: Roselands Hi Fi, Gallery Level South Hurstville: Selsound Hi Fi. 803 King George’s Road Summer Hill: Fidela Sound Centre. 93B Liverpool Street Sutherland: Sutherland Hi Fi, 5 Boyle
Street Waitara: Hornsbv Hi Fi, 71 Pacific Highwa\ Westleigh: Sound Incorporated. 16 Wcstleigh Shopping Centre NEW SOUTH WALES COUNTRY. Albury: Haberecht’s Radio & TV, 610 Dean
Street Bega: Easdowns. 187- 191 C.arp Street. Bowral: Fred Haves. 293 Bong Bong Street Broken Hill: Pee Jav Sound Centre. 364 Argent Street Gosford: Gosford Hi Fi. 163 Mann Street; Miranda Stereo
& Hi Fi Centre. Cnr Donnison & Baker Streets. Moss Vale: Bourne’s Merchandising, 1 White Street . Newcastle: Ron Chapman Hi Fi. 880 Hunter Street; Eastern Hi Fi, 519 Hunter Street Nowra: Nowra
Hi Fi. Shoalhavcn Arcade Taree: Taree Photographies, Graphic House, 105 Victoria Street Wagga Wagga: Haberechts Radio & TV, 128 Bavlis Street Wollongong: Hi Fi House, 268 Keira Street;
Selsound Hi Fi. 2-6 Crown Lane A.C.T. Civic: Allied Hi Fi. 122 Bunda Street. Fyshwick: Allied Hi Fi, 3Paragon Mall. Gladstone Street. QUEENSLAND. Brisbane: Chandlers, 120 Edward Street.
Chandlers. 399 Montague Road . West End. Stereo Supplies. 95 Turbot Street, Tel Air Electronics, 187 George Street . Nambour: Custom Sound, Currie Street Mt. Isa: The Sound Centre. West Street.
Rockhampton: Chandler’s. 144 Alma Street Southport: Stokes Electronics, Scarborough Street SOUTH AUSTRALIA. Adelaide: Ernsmiths. 48-50 King
W'llliam Street; Flinders Trading Co.. 55 Flinders Street, J B Electronics , 115 Gouger Street Blackwood: Blackwood Sound Centre. 4 Coromandel Parade
Glenside: Steiner Electronics. Convgham Street Moana: Bob Carmen, 185 Commercial Road. VICTORIA. Melbourne: Douglas Hi Fi, 191 Bourke Street;
Warrnambool: A. G. Smith. 159 Liebig Street WESTERN AUSTRALIA. Perth: The Audio Centre. 883
Wellington Street Calista: Hub Hi Fi, Kwinana Hub, Gilmore Avenue. East Victoria Park: Japan Hi Fi, 889 Albany Highway Nedlands. Audio Distributors.
Broadway Shopping Centre. Broadwav Midland: Midland Audio. 16B Great Northern Highway. Mosman Park: Audio Distributors, 14 Glyde Street W.A.
COUNTRY. Bunbury: Aabel Music. 130 Victoria Street Kalgoorlie: Hambley’s Hi Fi. Shop 13. Central Arcade. Hannan Street TASMANIA. Burnie: James
Loughran & Sons. 29-31 Wiltuot Street Hobart: Quantum Electronics. 181 Collins Street Launceston: Wills & Co.. 7 Quadrant NORTHERN TERRITORY.
Darwin: Pfitzners Music House, Smith Street.
*Thc Complete Protection Plan docs not cover equipment purchased outside Australia t Recommended retail price only.
70613R
AKAI
The name you don't have to
justify to your friends.
6
ELECTRONICS Australia, December, 1976
gives you that and
more.
At $289 R.R.P. with base and
cover, or only $479
complete with base, cover,
S.M.E. 3009 arm and
Stanton 681 eee, how can
you resist.
P.S. If this isn't the ultimate
turntable, we'd like
to know why.
* Measurements
taken from 1
authoritative U.S.
"F.M. Guide"
May 1976.
Sole Australian Distributors:
AAAAALERQVA _
Ul/Ull INDUSTRIES
156 Railway Pde., Leederville,
Western Australia 6007.
Phone 81 2930.
N.S.W. Office:
100 Walker St., North Sydney.
2060. Phone 922 4037.
VICTORIA Office:
103 Pelham St., Carlton 3053.
Phone 347 7620.
□ - 80 dB rumble
□ 0.04% wow and flutter
□ continuously variable
speed range through
a servo controlled
d.c. motor...
□ push-button selection
of 78, 45, 33V3 r.p.m.
does this make
the ultimate
turntable?
ELECTRONICS Australia, December, 1976
7
Some of the finest
musical instruments made
are UBL loudspeakers.
Our music instruments loudspeakers are available Australia wide.
Enquiries to: JBL, K100, P.O. Box 6, Brookvale. 2100.
The famous
JBL T-Shirt.
You’ve just said a mouthful. Now send me
my JBL T-Shirt, I enclose $5.00 for each
one making my cheque /money order $ . . .
My size is
Her size is.
Name . .
Address
Large
Medium
Small
Total
) T-Shirts
) T-Shirts
) T-Shirts
)
Postcode
'Musician’s WetSuit”
Send to: JBL, P.O. Box 6,
Brookvale. 2100
EH
T
ELECTRONICS Australia, December, 1976
Hi Fi News
AIWA wants some of the hifi action
Reflecting yet another significant move on the local hifi scene, AIWA
Australia Pty Ltd are beginning to make their presence felt with an
approach to selected dealers throughout Australia and with new-image
publicity headed up by colour commercials on major TV channels.
by NEVILLE WILLIAMS
To talk with AIWA Australia's General
Manager, Ian Woodhouse, is to receive
the multi-message: AIWA is big in hifi,
and especially in cassette players; AIWA
has a whole string of new quality
products in the pipeline; AIWA products
will be available where and when you
want them; AIWA is aiming to give the
best and fastest back-up service in the
business.
Behind the local enterprise is the
parent company in japan, whose name
bears an unfortunate resemblance to the
initials of Amalgamated Wireless (Aus¬
tralasia) Ltd. Perhaps that's why the
television adverts tend to stress the
pronunciation "Ay-ee-wah". Around the
company headquarters itself, however,
you are more likely to hear just plain
"Eye-wah".
Take your pick, as long as you don't
say: "A . . W . . er . . I . . er . . A"!
When the Company was first founded
in Japan in June 1951, it was registered
under the name Aiko Denki Sangyo
Kabushiki. With a capital of one million
Yen, its stated purpose was to manufac¬
ture and sell radio receivers and other
communications equipment. In fact, the
initial effort gravitated towards the
production of carbon, crystal and mov¬
ing coil microphones, of which the DM-1
dynamic became the best known. In
1955, the* variable reluctance mono
phono cartridge also attracted a lot of
attention.
NHK - The Japanese National Broad¬
casting Network — subsequently
appointed Aiko Denki as its leading tech¬
nical study factory and this, together with
a move into higher quality ribbon
microphone manufacture, necessitated
successive increases in capital to 100-
million Yen in 1959.
The same year saw the Company name
change to AIWA Co Ltd, followed by a
trebling of capital, listing on the Tokyo
stock exchange, and the establishment of
a major subsidiary in Chicago, USA.
1964/5 saw the development and
marketing of Japan's first compact cas¬
sette tape recorder/player, using the
then new Philips cassette format. About
the same time, Japan's first uni¬
directional moving coil microphone
appeared, the DM-47. Since then, AIWA
have developed and marketed a wide
variety of cassette recorders and players,
ranging from straight portables, through
‘cassette/radios, car cassettes and car¬
tridge players, to modern stereo cassette
decks, and integrated entertainment
centres: cassette/disc/receiver/
amplifier in one assembly.
AIWA products tended to filter on to
the Australian market relatively early in
the Company's history. Many will
remember the DM-1 moving coil
microphone, while the DM47 was very
popular for sub-professional P.A.
applications, by reason of its directional
qualities and the advantage it gave in
potential acoustic feedback situations.
Until fairly recently, AIWA products
were distributed in Australia by Goldring
and, in this era, the AIWA name became
Featuring prominently in AlWA's current publicity is the
AD-6500 front loading cassette deck (top) which features
automatic loading and illuminated cassette aperture. It has all
normal facilities including Dolby-B and provision for three
grades of tape , excellent specifications and a front panel DIN
socket for easy access. The matching AM/FM stereo receiver
below , type AX-7500, has full access and control facilities and
a rated output of 33W RMS per channel into 8 ohms.
Photographed at an AIWA dealer presentation at the Sydney
Opera House: Centre is AIWA Director Mr Hiroshi Kohjimoto ,
and left Mrs Harume Kohjimoto. On the right is AIWA Manag¬
ing Director for Australia Mr. James D. Cobb.
pi CPTROMIPQ AiiQtmlia npr.pmhftr 1976
Jtone/*
Rolling
ftudio.
A complete recording studio in a van? For Mick Jagger, it’s almost a neces¬
sity. Mick and the Stones can be inspired to produce their next hit anytime;
but when they’re on tour or vacationing, the best recording studios aren’t
always around the corner. For these moments of midnight inspiration, the
Stones rely on their Shure-equipped mobile studio for the unmatched record¬
ing perfection they insist upon. Whether in a recording session or on stage,
the Stones’ Shure SM53, SM58, SM5C, SM33, and SM54 microphones are
their assurance of consistent quality and natural sound.
Three more new Microphones from the Shure range.
Model PE52 Vagabond Shure SM1 1 Dynamic Element PE5EQ. The first
Close-Talking Microphone Lavalier Microphone Equalizer Microphone.
AUDIO ENGINEERS P/L
342 Kent Street,
SYDNEY 2000 N S W.
AUDIO ENGINEERS (Vic.) AUDIO ENGINEERS (Qld) ATHOL M. HILL P/L
2A Hill Street, 57 Castlemaine Street, 1000 Hay Street,
THORNBURY 3071 Vic. MILTON 4064 Qld. PERTH 6000 W.A.
AE110/FP
10
ELECTRONICS Australia, December, 1976
largely synonymous in Australia with por¬
table radios and cassette radios. The fact
that AIWR also manufactured up-market
stereo equipment was less well known.
When AIWA Australia Pty Ltd was
established in late 1975, one of the first
objectives was to extend the Company
image in Australia to the other end of the
market spectrum; to ensure that AIWA
was represented in the hifi salons with
appropriate product lines, as well as by
battery portables in the department
stores. In fact, the "portable" lines are
being deliberately rationalised to
simplify marketing— and customer
choice— in this area.
Meanwhile, the Australian Company
headquarters at 14 Gertrude St, Arncliffe,
NSW is rapidly taking on the character
of the new-look organisation.
Along one side of the upstairs show¬
room is a display of the smaller items
which have long been associated with
the AIWA name in Australia, ranging
from a first-size cassette recorder player,
through conventional portable tape
players to a 4-speaker compact system
intended for small flats and home units;
from routine portable receivers to multi¬
band receivers intended for the enthu¬
siast and ethnic DX and short-wave
listener market.
Along the other side of the showroom
are racks of hifi stereo cassette decks, top
loading, inclined panel loading, and front
loading— including the nifty automated
system being featured in the TV commer¬
cials. AIWA are more than happy for the
specifications to be compared with those
of comparable models from other manu¬
facturers.
As well, there are amplifiers, receivers
and integrated cassette/receivers, a belt-
driven turntable and a range of loud¬
speaker systems, which is in the course
of being expanded.
Downstairs, there is a service centre,
spare parts and bulk stores, staffed by
technical people familiar with the AIWA
range of products.
GOLDRING DOING THINGS IN STYLI!
According to Mike Dean , General Sales Manager for Goldring Sales & Service Pty
Ltd , his company will be placing renewed emphasis on the sale of replacement styli
and pickup cartridges. Typifying their approach , the Company operated a stylus
advisory centre at the Sydney Consumer Electronics Show , using an inspection device
which gave a 200-times up view of suspect stylus tips. Goldring is planning a series
of in-store promotional and educational centres to alert record users to the need
for regular stylus inspection and replacement. (Goldring Sales & Service Pty Ltd , 26-28
Ricketty St, Mascot 2020.)
And elsewhere in the building— we
almost forgot-are the— administrative
offices!
As Managing Director J.D. (Jim) Cobb
is not backward in reminding hifi dealers
around Australia: AIWA is into the pres¬
tige market, boots and all!
DECCA CASSETTES
Our article in the October issue of
"Electronics Australia", about the disap¬
pointing quality of many pre-recorded
cassettes, was mirrored in the American
"Audio" magazine for the same month.
On the basis that the average pre-
Miniature mic. for home moviemakers
With a diameter of 18mm and a depth
of 9mm , Sennheiser's new MKE 10
"Micromike" (left) should appeal to
home moviemakers and others who
need a microphone small enough to pin
unobtrusively to clothing. An electret
type with omnidirectional pickup , it can
be used directly with any tape recorder
with a DIN 45 594
input with integral
DC supply connec¬
tion. Where this is
not available , one or
two Micromikes (for
stereo) can be used
with the slim battery
supply module
shown to provide
signal for normal
inputs. The Micro¬
mike is due for
release in January
1977. (In Australia: R.
H. Cunningham Pty
Ltd , 493-499 Victoria
St , West Melbourne.)
recorded cassette compared poorly with
its disc counterpart, columnist Bert
Whyte was most interested to attend a
demonstration in New York of up¬
graded cassettes being released under
the "London" label.
As Bert Whyte points out, this is the
label used in America for releases by Bri¬
tish Decca. One of the prominent figures
at the New York Demonstration was
none other than Arthur Haddy, the man
largely responsible for Decca's notable
ffrr discs, which immediately preceded
the microgroove era.
Guests at the demonstration were
invited to compare directly the new Lon-
don/Decca cassettes with 1 Sips copies
of the same material, being free to check
levels and operate the A/B switching to
suit themselves. While Bert Whyte had
some reservations about the choice of
loudspeakers and the characteristics of
the hotel room involved, there seemed
to be little doubt that the new cassettes
were way above average.
This was confirmed when Bert Whyte
was able to play a selection of the Lon-
don/Decca cassettes on his own equip¬
ment and share reactions with other
expert listeners.
Out of this came the very natural ques¬
tion: what was the explanation for the
apparent improvement in quality? While
various companies had made conscious
efforts, in the past to improve the quality
of pre-recorded cassettes, in general
they had tended to come unstuck for
economic reasons. As a result, cassettes
have tended to gravitate to a level
adequate for casual listening but short of
1 1
ELECTRONICS Australia, December, 1976
'
A screwdriver and about Vi an hour
is all you need to build this 40 watt
Philips speaker system.
Philips make it easy and inexpensive
for you to own a professional
speaker system. Assemble it yourself
in about 30 minutes and you have
40 watt (RMS) capacity speakers
to complement your hi-fi gear.
PHILIPS
The AD8K40 Speaker Kit includes:
• 2 precut, pre-finished wood grain
cabinet enclosures with
pre-painted baffle boards.
• 2 mounted grill cloths with
pre-painted baffle boards. •2x8”
woofers. #2x1” dome tweeters.
• 2 x 2-way crossover networks with
leads and fas tons fitted.
• Innerbond lining. • Wood screws.
• Wood glue. • Caulking compound.
Plus full assembly instructions.
For further information contact
PHILIPS
Electronic Components and Materials,
P.O. Box 50,
Lane CoveN.S.W. 2066.
Or phone 42 1261 or 420361
Branches in all States.
\
12
ELECTRONICS Australia, December, 1976
153.0188
HIFI NEWS — continued
accepted domestic hifi standards.
It transpired that Decca's cassette
production is concentrated in the village
of Bridgenorth, 140 miles north of Lon¬
don and not far from the Welsh border.
And the quality of the cassettes that
emerge from the Bridgenorth complex is
not the result of any revolution in tech¬
nology, but of meticulous attention to
detail and quality control.
In one of its other facilities, Decca
makes its own cassette shells, with due
attention given to something like 400
dimensions, all likely to have some affect
on the behaviour of the tape— as eviden¬
ced in wow and flutter on the user's
deck. For the same reasons, the shells are
ultimately welded together rather than
screwed, because Decca research sug¬
gests that screwing produces more
stresses, with a greater chance of
misalignment.
Inside the shell, guide rollers have
been replaced by solid posts of slippery
Delrin, eliminating another source of
erratic tension, due to eccentric rollers or
sticky bearings. A special graphite coated
liner provides further lubrication and
control, while tiny aluminium rods, press
fitted into slots in the hub, provide a
highly controllable method of locking
the tape to the spools.
As a result of these measures, Decca
claim a particularly low figure for azimuth
error or tape wander— therefore for mis-
tracking at the highest frequencies— no
matter what the physical position of the
cassette.
The surprising thing, however, is that
Decca have made no concession to
copying speed, which might prejudice
unit production cost. The slave tape runs
at 60ips, or 32 times normal speed, while
the bias oscillator operates at 10MHz.
However, while the technology and
equipment is routine enough, Decca
engineers rework the decks before they
are put into service, mounting special fer¬
rite heads on adjustable plates which
permit ultra-fine setting of azimuth. As
well, the tape guidance components are
modified to reduce the abruptness of
direction changes and to improve the
intimacy of contact between tape and
head.
The tape itself is selected to suit, not
only the equipment, but the nature of the
program to be recorded. At the time of
reporting, Decca was using either BASF
duplicating tape or a high energy grade
of Memorex, giving an extra 8dB of head-
room.
Full Dolby-A is used for the running
master, being decoded to Dolby-B for
the cassette copies actually sold over the
counter.
Experience would seem to indicate
that Dolby-B is not a panacea for all
recording ills and, if used carelessly, may
cause as many problems as it cures. But
CENTREX: Quality sound on the move
Curiously, while AIWA Australia are
expanding up-market (see preceding
pages) Pioneer Electronics Australia
are looking the other way. Already well
established in the domestic hifi market,
they have launched into the portable
and "transportable'' market with Cen¬
trex (by Pioneer): "Quality sound that
moves around
Pictured above is the most "domes¬
tic" of the new Centrex products— an
AM and FM /stereo receiver with in¬
built stereo cassette recorder/ player
and a "piggy-bank" 3-speed record
changer with magnetic cartridge and
diamond stylus. Power output is a
modest 4W RMS per channel but it has
all the facilities necessary for disc or
cassette listening in a flat or small
home unit. Price, complete with a pair
of 2-way speaker systems, is $449.
Simplest of the portable cassette
receivers (top right) is the RK-112,
which has a recommended retail price
of $99. It offers coverage of the normal
AM band (525- 1 630kHz), the FM
band in mono mode (88-108MHz), in¬
built mono cassette record /replay
deck, in-built mic. and provision for
external mic. Powered from four 1 ,5V
D cells, or from the mains, it is credited
with an output of 2.3W "music
power". Other features include tape
auto stop, automatic recording level
control, and a "sleep" function.
The RK-222 (centre right) has the
same general stylihg as the RK-112
but has more facilities and retails at
$135. Additional facilities include a
short-wave band (5.9-1 6MHz),
microphone mixing, tape footage
counter, and battery and level meter.
The present top-of-the-line Centrex
portable is the RK-888 (bottom right).
It has a quite different styling with slide
controls and a facia that is akin to a
domestic cassette/receiver. Apart
from the more ambitious styling, it
offers higher specifications, separate
bass and treble controls, a memory
style counter, and a two-way loud¬
speaker system. Recommended retail
price is $ 1 95.
Centrex will be available initially in
New South Wales and Victoria, with
other states to follow later in the new
year. (For further information: Rod
Knapp, Pioneer Electronics Australia
Pty Ltd, 1 78-1 84 Boundary Rd,
Braeside, Vic. Phone (Melbourne)
90 9011.)
hLhUIHUNICS Australia, December, 1976
13
BOGEN /TECH-CRAFT NOW HANDLED BY AUDIO TELEX
A new name-Tech-craft-and a whole range of new look
professional equipment is currently being introduced on to
the Australian market by Audio Telex Communications Pty Ltd.
But behind the new name is a very old one, Bogen (now the
Bogen Division of Lear Siegler Inc.) a major supplier of quality
audio equipment in the USA since 1932.
In their newly announced Tech-craft product line, Bogen
have drawn on their expertise in the hifi field to exploit the
"system" approach, in which the amplifier is regarded as cen¬
tral, other peripheral equipment being designed to be com¬
patible with it. The policy ensures, at the one time, flexibility,
along with a predictable high quality end result.
The Tech-craft range is therefore seen as ideal for profes¬
sional use in auditoriums, concert halls, theatres, churches,
sporting arenas, &c-in fact, anywhere the need arises for high
quality sound reinforcement.
Tech-craft amplifiers are available in three power ranges,
60, 125 and 250 watts. With continuous professional rating at
+ 55°C ambient air temperature, they produce less than 1%
total harmonic distortion from 25 to 22,000Hz. All the
amplifiers offer 25V or 75 volt output, as well as a direct output.
The amplifiers are designed for standard 19" rack mounting
and have a brushed nickel steel finish.
Two Tech-craft mixer/amplifiers are available, the smaller
TCM 100 providing four mic inputs, one convertible to line
and one high level input. Its big brother, the TCM 200, is
designed to handle 8 inputs each controlled by linear slide
pot and capable of handling almost any type of audio input
by means of plug-in modules. Each input channel has an LED
overload indicator and a 30dB continuously variable attenua¬
tor to adjust for peak overload. Both mixers feature active mix¬
ing, with negligible interaction between inputs. In fact, the
microphone channel isolation is 80 dB. Both mixers feature
large illuminated VU meters and multi channel input extend¬
ers.
Another unit designed expressly for the Tech-craft sound
reinforcement chain is the Vi octave equalizer model TCE 200.
It contains 24 filter sections providing up to 14 dB of either
boost or attenuation in Vi octave increments. Its rated output
is 18 dBM into a 600-ohm load with less than .5% distortion;
residual noise is 80 dB below the rated output. Like other Tech-
craft products in the range the unit operates from either AC
or DC
Other Tech-craft components include compressor/line
amplifier model TCC 200, 150 watt mono/stereo bi amplifier
model TCB1 /1 50 arid two mixer power amplifiers. Model TCA
60 and TCA 125.
From the top: A Tech-craft dual concentric loudspeaker ; the
TCM 200 8-channel mixer; TCB 125 125W solid-state power
amplifier; TCE 200 spectrum equaliser.
Rounding out the Tech-craft line are 23 loudspeaker system
components including 3 compressor drivers, 4 radial horns,
3 multi-cellular horns, 3 low frequency speaker systems, 1
wide-range three-way speaker system, two co-axial loud¬
speakers, and the required crossover networks and hardware.
This wide range of components will fill system requirements
from the smallest rooms to stadiums with equal compat¬
ibility.
The Bogen-Tech-craft range of sound products are distri¬
buted in Australia by Audio Telex Communications Pty Ltd.,
54 Alfred St, Milsons Point, Sydney. Also at 828 Glenferrie Rd,
Hawthorn, Vic.
HIFI NEWS — continued
Dolby-B processing, climaxing the kind
of quality control that Decca are
apparently seeking to maintain, can well
add the final touch of lustre.
An agreement signed recently in Japan
gives the Components Division of Ples-
sey Australia sole Australian distribution
of the internationally-known Foster and
Fostex loudspeakers.
The Foster Electric Company has five
plants in japan and others in Singapore
and Taiwan. Contractors for sound
equipment installed in the Sydney Opera
House chose Foster speakers and more
are being supplied through Plessey.
The company produces loudspeakers
—from paper pulped for the cones to the
14 ELECTRONICS Australia, December, 1
end product— ranging in size from 25mm
horn tweeters to 305mm ones for
amplifying guitar music.
As well as Foster speakers for general
purpose, hi-fi and on-stage music
amplification, Plessey will also market
the Fostex range designed for the
ultimate hi-fi enthusiast.
The agreement— described by Mr Wes
Oliver, manager of Plessey electronic
components, as most important to his
company— will strengthen Plessey in the .
audio field.
Importation of the high-quality
speakers is linked with two other moves
by Plessey in the audio business— a new
range of Garrard turntables and modules
(available early in 1977) and improved
versions of the complementary range of
locally assembled enclosed speakers.
976
Earlier in the year, we drew attention
to the anomaly arising from the practice
of supplying hifi equipment fitted with
2- wire power cord and a 3-pin plug.
It was with interest, therefore, that we
received the following advice from
Pioneer Electronics Australia Pty Ltd,
over the signature of their Publicity/
Promotions Officer, Mr. R. Knapp:
"In recent months the desirability of
using 2-pin mains plugs and 2-wire leads
in hi-fi equipment has been questioned.
"Pioneer Electronics Australia Pty. Ltd.
have been acutely aware of this and are
currently taking action to rectify the
situation.
"By the end of this year all Pioneer Hi
Fi equipment, designed for the Australian
market, will be fitted with approved
3- core Mains Flex and 3-Pin Plug."
WHERE THERE'S A HEED
THERE'S A STANTON
Stanton have always satisfied the needs of those whose job it is to play records — of any sort. Here are
some of the specific record playing tasks Stanton have been called on to cope with: —
• Lacquer masters • Metal Mothers • Quality Control • Equipment Calibration
• Transcribing of historic 78’s with non standard grooves • Transcribing of
cylinders • Back cueing in Radio stations and Discotheques.
Stanton developed specific cartridges and styli to satisfy these needs.
Another need arose.
Hi Fi enthusiasts and music lovers wanted per¬
formance as close as possible to the unequalled
681 EEE but at a substantially lower price.
Accepting the challenge, Stanton produced the
680EE. It has many of the universally acclaimed
qualities of the 681 EEE. It tracks at the same pressure
as the 681 EEE (0.75 — 1 .5 gms) it has the same unsur¬
passed channel separation of 35dB (at 1KHZ) and its
frequency response is almost as wide.
At $51 (R.R.P.) it’s almost too good to be true.
Audition one today and judge for yourself.
Sole Australian Distributors:
PTY
LTD
Head Office, WA: N.S.W. Office: Victoria Office:
156 Railway Parade, Leederville, 100 Walker Street, North Sydney, 103 Pelham Street, Carlton,
Western Australia, 6007. N.S.W. 2060. Phone 922 4037. 3053. Phone 347 7620.
Phone 81 2930.
Available at quality-conscious
Hi-Fi dealers
throughout Australia.
LER 149
ELECTRONICS Australia, December, 1976 15
SONY HI-FI NEWS No3
New from Sony:
Front loading Cassette Decks
SONY
*0 Wt*
a
Bow
TC206SD
Sound that rivals reel-to-reel in a
space only one sixth as high.
Sony's new front loading cassette decks are
loaded with features. For example the
TC206SD with full range separate bias and
equalisation selectors to handle high quality
ferric, chrome dioxide and Sony’s superb
double coated ferri-chrome cassettes. Fully
flexible Dolby* controls with multiplex
filtering to get the best from FM broadcasts.
LED peak indicator as well as easy to read
VU’s. Automatic shut off. Lockable pause
key for precise cueing. Sony's famous long
v life Ferrite and Ferrite head. Illuminated
cassette well and upright tape positioning
for easy viewing of cassettes. Featuring the
new 'Soft Eject’ mechanism.
And the sound? Strictly ‘Front of the House’.
Virtually linear smooth response over a
tremendous range of 20-16,000Hz (FeCr,
CrC>2 tape). Wow and flutter at reel-to-reel
standard of 0.08%. Signal to noise - an
amazing 59dB.
If you want space saving, front-loading
convenience and quality sound, check the
range of Sony cassette decks soon; the
TC206SD for superb sound, the TC209SD
strictly for connoisseurs with specifications
to match. And the budget priced TC 186SD
for Sony quality - at a significant saving.
‘Dolby is a trademark of Dolby Laboratories Inc.
Hear the difference research makes .
16
ELECTRONICS Australia, December, 1976
New AWA monitor
uses duplex woofers
A new loudspeaker system currently under development by AWA
employs a novel variant of the reflex principle, to obtain a response
down to below 30 Hz in an enclosure of moderate size, together with
good efficiency and high power rating. Designated as AWA type
DD88M, it is envisaged as a professional monitor, or for high quality
reproduction in the home.
By NEVILLE WILLIAMS
During the last decade, research into
drivers and enclosures, much of it
originating in Australia, has taken most of
the guesswork and the. folklore out of
loudspeaker system design— at least as
far as the bass end is concerned. It has
reached the stage where, as recently
reported, procedures devised by Aus¬
tralian engineer Neville Thiele have been
translated by Wharfedale of England into
a computer program. On request, the
computer can print out a range of
options covering driver and enclosure
parameters and the related frequency
response characteristics.
While such methods can predict quite
reliably how a proposed system will
behave in the bass register, they certainly
cramp the style of an engineer trying to
dream up a new and more saleable
product. He can play around to his
heart's content in the middle and top
register and do all sorts of things in terms
of presence, directionality, phase
linearity and so on; but the bass charac¬
teristic will be the predictable outcome
of whatever set of compromises he set¬
tles for.
Some twelve months ago, while the
rest of the Ashfield staff were enjoying
annual leave, AWA's long-time
loudspeaker engineer, Wal Barlow, was
pondering the vexed question of how he
might manipulate established design
parameters to end up with a system
which would go down reliably to at least
30Hz, without incurring the likely penal¬
ties: prohibitively expensive driver(s),
unduly large enclosure, or embar¬
rassingly low conversion efficiency.
Behind the exercise was a liberal help¬
ing of good, old-fashioned purist pres¬
sure. If one examines the response
curves of typical modern hifi loud¬
speaker systems, the majority of them do
A front view of the DD88M monitor , with
fret removed . Note the recessed woofers
and the port , which also serves as a
base.
indeed have a fairly flat response down
to a deliberate "corner" frequency,
below which output rolls off at either 6dB
or 12dB per octave. The problem is that
the corner frequency is usually in the
range 70Hz to 40\~\z, rarely going below
that.
Figures near .the top end of the range
are justified on the basis that they
represent the best possible compromise,
for a given design, between size, sensi¬
tivity and power handling capability.
Figures at the lower end of the range are
justified on the basis that musical
« frequencies below 40Hz occur only
rarely, and not at all in a large amount
of typical program. But, in any case, a sys¬
tem with a smooth response and roll-off
can be assisted by a discrete amount of
bass boost in the amplifier.
But, whatever the truth behind this
kind of rationalisation, it never really
satisfies the dyed-in-the-wool purist. If
theory suggests that some program
material will contain frequencies down
to 30Hz, then that's what the loud¬
speaker system should be designed for—
without the aid of bass boost and despite
the limitations of typical listening
rooms!
And that's the kind of pressure that was
behind Wal Barlow's initiative.
What emerged from it all was the
novel approach behind the AWA
DD88M monitor— not an idea that con¬
travened theory but one that managed to
manipulate the parameters towards the
desired end result.
Fundamental to the proposition was
the assumption that any system which
might meet the objectives, would be a
reflex design, because of the vital con¬
tribution that a port can make to output
and efficiency at the bottom end. Flow¬
ing from this assumption, Wal Barlow
worked through the conflicting con¬
siderations— and they are summarised
below from the DD88M background
literature:
ENCLOSURE VOLUME: The larger the
enclosure, the less it tends to push up
the natural resonance of the selected
driver. However, enclosure size is limi¬
ted by customer demand, which tends
to taper off with increasing enclosure
size and mass. Price is also a deterrent,
because it costs more to manufacture,
package, store and deliver large and
rigid enclosures.
CONE AREA: A small cone is less
affected by an enclosure of limited size
than a large cone, making it possible
to achieve a lower corner frequency.
However, to move a given volume of
air, thereby producing a given sound
level, a small cone has to travel through
a greater distance than a large cone;
this imposes its own problems and
limitations. Beside that, small cones
tend to have less customer appeal.
CONE STIFFNESS & MASS: Both are
involved in determining the driver's
natural bass resonance. The cone
suspension must exhibit reasonable
ruggedness and an adequate restoring
force for mechanical reasons, resulting
in some "stiffness"; too much stiffness,
however, raises the resonance unduly,
making it difficult to design for a
smooth, extended response. Higher
cone mass has the opposite and
desirable effect of lowering the natural
cone resonance but it must be
matched by an increase in the magne¬
tic circuit flux in order to ensure
adequate electrical damping and to
prevent the development of bass
"boom".
MAGNETIC FLUX: Most high quality
drivers already have more ambitious
and costly magnetic systems and there
may not be scope to increase the mag¬
netic flux to match any significant
increase in cone mass. In fact, the mag¬
netic circuit of most high quality
ELECTRONICS Australia, December, 1376
17
The Luxor Swedish Sound5
A superb range of record players designed for precision and reliability
from Sweden’s largest manufacturer of high-quality stereo systems
In 1923, at Motala in Sweden, Luxor
first began serial production of radio
sets. Since that time, Luxor have grown
to be, among other things, Sweden’s
largest-selling range of record players.
Magnetic cartridge reduces
record wear
Luxor record players feature a
magnetic, dynamic cartridge that gives
a low stylus pressure to reduce record
wear.
Luxor’s own pick-up arm system
Luxor have developed a system of
their own for the mounting and balancing
of the pick-up arm. Emphasis is placed
on precise design, ease of use and
reliability.
Transparent, adjustable lid
The lid will remain open any
position, automatically. And can be
lowered safely and completely during
playing.
Adjustable stylus pressure
To prevent skating and damage
to records, the Luxor System gives
convenient pressure adjustment, along
with precise control.
The mechanics of superb sound
Special features include a 16-pole
synchronous motor and belt-drive for
low wow and flutter. And switchable
automatic stop which completely
disengages the pick-up-arm.
They look as good as they sound
Luxor record players combine a
careful attention to detail with an unmis¬
takable touch of design flair. Elegant
and sleek. In a superb range of exterior
cabinets blending with sophisticated,
functional control panelling.
The superb Swedish sound
As Sweden has developed in the
world of music, so Luxor have developed
in reproducing that sound. The more
you know about Luxor record players,
the more impressive they sound.
£uxor
of Sweden
To: Luxor, P.O. Box 307,
Collingwood, Vic., 3066.
I would like to know more about
the Luxor range of stereo systems,
including record players.
I am interested in becoming a
Luxor Distributor □
I am interested in becoming a
Luxor Stockist □
Mr/Mrs/Miss_
Address.
.Postcode.
C/- Luxor, 77 Wellington Street,
Collingwood LUX 145
18
ELECTRONICS Australia, December, 1976
AWA MONITOR USES DUPLEX WOOFERS
speakers is already saturated, so that
a further increase in cone mass is really
not an option.
Faced with these limitations, the
hopeful designer would seem to have lit¬
tle room to move, but Wal Barlow came
up with a novel answer which is currently
the subject of a patent application. He
simply took two suitable bass drivers and
mounted them face to face on the
enclosure baffle, supplying them with
signals of opposite phase, so that both
cones move in the same direction.
By so doing, he produced a composite
bass driver referred to in the patent
documents as "Duplex Drive". It has the
following interesting characteristics:
• Double the stiffness of either driver
alone. This is counter-balanced by:
• Double the mass, since the composite
cone is really two cones, plus a small
amount of air trapped between them.
These two effects combine to
produce:
• The same fundamental bass
resonance as either driver alone. But
the modified characteristics-more
stiffness, more weight— both tend to
make the driver less affected by
enclosure volume. As a result:
• Enclosure design can be guided
towards a lower corner frequency for
a given internal volume than would be
possible with only one of the com¬
posite pair. And fortunately:
• Magnetic damping is maintained at
the correct level because there are
two distinct magnetic circuits to cope
with the extra mass.
• Linearity appears to be improved
because the cones are operating vir¬
tually in push-pull, with a tendency to
cancel non-linear suspension charac¬
teristics. Another bonus is that:
• The soft surround tends to be blown
less by air pressure, each surround
being protected by the other.
The enclosure, as pictured, was a
prototype submitted for our comment;
the final DD88M may exhibit some cos¬
metic changes. It measures 765mm high
x 460mm wide by 335mm deep and
weighs 29kg. As such, it is a fairly typical
free-standing system, certainly larger
than some overgrown "shelf"
enclosures, but nowhere near the size
and bulk of the big ones that married
couples argue about!
It is a reflex system but the internally
damped port is provided in the recessed
base on which the enclosure rests. The
arrangement contributes to the styling
but it also make possible a port with a
generous cross-section and low air velo¬
city, venting at floor level— definite plus
factors.
The composite bass drive is provided
by two specially selected "Coral" 200mm
woofers mounted on a sub-baffle, so that
the rear of the front speaker does not
protrude. The composite pair is rated to
take 80W of program power and, since
the sensitivity is fairly average for a hifi
system, the sound output is substantial.
AWA stress that the rating is all the
more significant because the system
operates in a fundamental mode to
below 30Hz without the need for bass
boost. In fact, maximum output from the
port, and therefore minimum cone travel
occurs at 27Hz. Thus, very low organ
notes which would tend to frequency
double and "muddy up" the bottom end
of conventional systems, tend to emerge
as fundamentals from the port, with the
cone itself exhibiting relatively small
travel.
The bass drivers handle frequencies up
to a nominal 500Hz, where a cross-over
network diverts the output to a 175 x
125mm cone type mid range driver. The
stated reason for choosing this type of
speaker, for the prototype system at
least, is that an oval cone tends to exhibit
less concentrated Bell tones because of
its distributed dimensions.
A 1-inch dome tweeter is used for the
upper frequencies, taking over above
5kHz.
Removal of the front fret reveals the
respective drivers and a recessed panel
carrying level switches for the mid-range
and tweeter. A calibration curve suggests
a response within a 4dB window from
27 Hz to 20kHz. Rated impedance is
shown as 4 ohms.
Questioned about the linear phase
concept, currently the subject of much
attention, Wal Barlow expressed the
conviction that phase was a pointer to
other things in electrical circuits but it
tended rapidly to become a random
thing in free space. Therefore, while
making no effort to stagger the frontal
alignment of the drivers, he had paid very
close attention to the divider network,
trimming the various legs to provide the
kind of signal required by each of the
drivers.
When we first heard the system in
action at the Sydney Consumer Elec¬
tronics Show, two things were evident:
first, the bass response was quite startling
in its profundity, as distinct from its
"thump" power; second the program
material selected to demonstrate the
unique quality was untypical of what
most people listen to most of the time.
We were therefore most interested to
have the opportunity to set the speakers
up in our own building, in a fairly
generous listening area, and to play
typical program material through them
from the Nakamichi System One,
reviewed in our current Year Book. By
way of comparison, we had a Philips
Elcoma System 14 in a pair of George
Hawthorn concrete enclosures.
On the first few tracks, picked more
or less randomly, there appeared to be
little difference in the bass end; both sys¬
tems were good, both were adequate
and the overall impression was that AWA
had merely come up with another way
of achieving a similar end result.
But then we dug out the theme music
from the film "Earthquake", containing a
segment of very high amplitude, very low
frequency earthquake noise, allegedly
going down to under 20Hz. That's when
the difference showed up. But is it logical
to create a special speaker system to hear
"Earthquake" music outside a theatre?
But thus alerted, we listened further to
still other material and the point had to
be conceded: just occasionally, when the
program reached down below 40Hz, the
A-B tests would show up the extra half¬
octave from the port as discernible extra
weight, way down.
Worthwhile? Worth whatever margin
of cost might be involved?
There's no simple answer to that but
it's what the purist approach is all about:
the effort to ensure that the system will
meet particular demands, even if they
occur only rarely!
In the middle register, we felt that the
DD88M was just a little too "forward" for
all round listening— arresting in its projec¬
tion of solo voice and instrument, but
with a trifle too much coming from the
one place in massed tones, as from full
organ, full orchestra, full choir, &c. There
was a level adjustment for the mid-range
and tweeter speakers but we felt that the
range of adjustment could have been
increased to advantage. Wal Barlow was
inclined to agree and it is likely that the
final model will be so modified.
So there it is-another original and
unique contribution to reflex
loudspeaker system design by an Aus¬
tralian engineer, and one that is sure to
grab the attention of his overseas coun¬
terparts.
When will the DD88M be available
commercially and for how much?
We expect within the early part of the
new year, and at a price level that will
be up-market but significantly below the
exotic imports. At the time of writing, we
doubt that anyone could say more than
that— not even AWA! $
WANT TO BUILD A 250W MUSIC SPEAKER SYSTEM?
—Then you should make sure to get your copy of the
1976/77 YEAR BOOK
Available now from all newsagents— price $ 1 .20
Or mailed to you direct from our office for $1.80
ELECTRONICS Australia, December, 1976
19
MICROPHONES
Part 3: Frequency response, directivity etc.
This series of articles is reproduced by courtesy of Sennheiser Elec¬
tronics and is intended to assist sub-professionals and amateurs who
need to use microphones, but without the advantage of formal acoustic
training. This section deals with the frequency response and directional
characteristics of practical microphones.
by G. PRAETZELand E. F. WARNKE*
FREQUENCY RESPONSE: The frequency
response (or bandwidth) of a micro¬
phone is shown in manufacturers'
publications, mostly in graphical form. As
an example Fig. 7 represents a frequency
range from 30 Hz to 17000Hz.
In Fig. 7 the frequencies from the lower
to the upper threshold of audibility are
plotted horizontally, while vertically the
output voltage of the microphone in the
"Decibel Scale" is shown. The following
should be said about this dB scale.
A decibel is not an absolute measure
like the metre, gram or Hertz. The dB sig¬
nifies a ratio of two numerical values.
Referring to the logarithmic perception
of loudness of the human ear, the decibel
was derived from the Brigg's logarithm
of a voltage ratio:
20 log U,/U2
or, correspondingly of a power ratio
10 log P1/P2
If these formulas present a problem,
the most important decibel values can be
obtained readily from the accompanying
tables:
voltage ratio power ratio dB
1.4
2
4
8
10
20
50
100
200
500
1,000
10,000
2
4
16
64
100
400
2,500
10,000
40,000
250,000
1,000,000
100,000,000
3
6
12
18
20
26
34
40
46
54
60
80
By way of further assistance, it is possi¬
ble to convert figures from the dB table
as follows:
example:
26 dB voltage ratio
26 dB = 20 dB -h 6 dB
‘Reproduced by arrangement with Sennheiser
Electronic. Translated by T. M. Jaskolski and
adapted for magazine publication by W. N.
Williams.
= (10 times) x ( 2 times) = 20 times
Decibels are used to show deviations
of the frequency response from straight-
lined curve, in order to match the loud¬
ness perception of the human ear.
Thus Fig. 7, as an example of a high
quality dynamic directional microphone,
shows at 5000Hz a lift of some 5dB above
the practically flat frequency response
between 100 and 1500Hz. However,
practical experience with just this type of
microphone indicates that such a lift is
often considered desirable, providing a
"brighter" recording.
Where this extra brightness is not
desired-depending on the ideas of the
sound engineer-Sennheiser has
provided its leading dynamic
microphone the MD 441 , with switchable
brightness. Experience has proved that
this microphone, in the great majority of
its applications, is used with the upper
response boosted.
DIRECTIONAL CHARACTERISTICS:
So far, we have assumed that a
microphone-and also, with limitations,
the human ear-receives the sound
uniformly from all directions, ie, are
omnidirectional. Their directional
characteristic in one plane is thus a circle,
while their spatial directional characteris¬
tic corresponds to a sphere (see Fig. 8).
In practice omnidirectional microphones
are to be preferred as reporter's
microphones for close talking. In this role
a particular advantage of the omnidirec-
Cardioid
Fig. 9. Cardioid microphone directivity ,
spatially presented. Sensitivity is mainly
to the front and sides.
- 2000 Hi
8000 H
The cardioid response in graph form/
taken in a horizontal plane. Note how
directivity varies with frequency.
Fig. 7. This response curve of the Sennheiser MD 421 is typical of the kind of data
supplied by manufacturers. The solid curve shows the nominal response and the
dotted curves show the tolerance limits.
20
ELECTRONICS Australia, December, 1976
tional microphone is its high insensi¬
tiveness to mechanical vibrations ie,
handling noise.
The omnidirectional microphone is
much less suited to recording distant
sounds, since it also picks up extraneous
noise and reverberation. For this job
microphones with distinct directional
characteristics are preferable. For a long
time the classic cardioid microphone
(Fig. 9) was considered ideal.
The cardioid directional characteristic
effectively attenuates sound from the
rear but is still sensitive to noise and
reverberation from other directions. Bet¬
ter results in this respect are obtained
with the super cardioid microphone, as
illustrated in Fig 10. Even better, in really
difficult situations, are those micro¬
phones with highly directional charac¬
teristics, as shown in Fig. 11.
In principle, however, all microphones
with such directional characteristics are
more sensitive to mechanical vibrations
and handling noise, as well as to wind
noise and to so-called "pop noises", ie,
Fig. 12. Anti-vibration sleeve for use with
tripod stands or table stands.
air shocks caused by explosive sounds,
than omnidirectional microphones. To
overcome this the microphone manufac¬
turers have to take special precautions.
An effective remedy against wind inter¬
ference is provided by "wind shields".
These do not affect either the sensitivity
or the frequency response of the
microphone when suitable material is
selected.
A special plastic foam is used for these
shields. It should not be confused with
conventional plastic foam as used for
packaging, or filling for cushions, etc.
Such material consists almost completely
of closed pores which strongly attenuate
sound at higher frequencies. The foam
used for the wind shields is made by a
special process in which the pores in the
greater part of the material have been
broken up, leaving only a skeleton foam.
This has no effect on the frequency range
concerned.
More expensive in manufacture but
somewhat more effective are wind
shields made of special silk. These
shields are placed at a greater distance
from the microphone's sound inlet and
thus achieve a much greater effect.
Effective measures against sensitivity
to mechanical vibrations are consider¬
ably more expensive. First, attention
should be paid to keep vibration away
from the microphone system proper.
This can usually be achieved by spring
suspension, either built into the tripod
mounting for the microphone, (Fig. 12)
Compensating coil
against magnetic interference
Bass attenuator
Rear spring
suspension
Rear inlet for
low frequencies
Resonator
fFigJri
The elaborate inside of the high quality studio
microphone MD 411. Suspension springs are
clearly visible; they isolate the “inner” microphone
against mechanical vibrations of the outer housing.
Stop pad
Oust shield
Rear inlet for
middle frequencies
Rear inlet for
high frequencies
Transformer for
brilliance emphasis
Stop pad
Can for low
frequency boost
Popp-screen
Front spring
suspension
2SO Hz - 500 Hz
WOOHz _ 2000Hz
4000Hz . 8000Hz
Fig. 10. The super cardioid response.
Note the sharp nulls at 120°.
Fig. 11. Response curve of a highly direc¬
tional (lobe) type microphone.
be shown that, in spite of the above
precautions, the microphone still
delivers a very low voltage which
evidently has no connection with any
external sound effects.
In all dynamic microphones with a
moving coil of 200 ohms impedance this
inherent microphone self-noise amounts
to almost exactly 0.8m V. It is caused by
a thermal electron movement in the cop¬
per wire of the moving coil and by the
molecular movement of the air on the
surface of the diaphragm.
Whether this noise voltage interferes
with the recording depends on the one
hand on the sensivity of the microphone
and on the other hand on the volume of
the sound to be recorded.
Let us assume, for instance, that we use
a dynamic microphone with a sensitivity
of only 0.1mV//ibar to record a speaker
at a distance of one metre. We could thus
reckon on a sound pressure of 1m bar. At
this sound pressure the microphone
would deliver a voltage of 0.1 mV. Refer¬
ring to the noise voltage of 0.8m V, we
would have only a signal-to-noise ratio
of 125 : 1 = 42dB! Should we, however,
use a dynamic microphone with a sensi¬
tivity of 0.2mV/Mbar, with other proper¬
ties equivalent, the ratio of useful voltage
to noise would be 250 : 1 = 48 dB.
The inherent self-noise of high quality
studio capacitor microphones is, related
to their sensitivity, about 7dB better so
that, in recording conditions as described
above, they could provide a signal-to-
noise ratio of up to 56 dB.
Against this, the self-noise of some
cheap electret capacitor microphones
(again related to their sensitivity) is up to
10dB less favourable than that of the
dynamic, so that their signal-to-noise
ratio would be down to 38dB in the
recording conditions described above.
or, in some microphones, into the hous¬
ing itself (Fig. 13). Such procedures will
usually reduce vibration problems to
negligible proportions.
SIGN AL-TO- NOISE-RATIO: When a
microphone is placed in a completely
quiet room, connected to a high quality
amplifier, free of noise and hum, it can
Thus, where the input sound level is
relatively high, and particularly where the
dynamic range is small, the high internal
noise of some microphones is of little
consequence. But for low sound levels,
and where there is a large dynamic range,
only those microphones with the lowest
internal noise will do.
ELECTRONICS Australia, December, 1976
21
Presented
with pride
Lencoclean L as shown optional extra
perfect sound reproduction
equipment! So, people who are looking for near¬
perfection in sound reproduction . . . listen to
Lenco. Combine this superb reproduction with
Lenco's very reasonable price and you have a
Photimport presents with pride, the Lenco range
of precision-engineered Hi-Fi turntables.
Australian test results have shown that wow and
flutter are almost impossible to measure in Lenco
Three superb Lenco turntables.
The L90 Lenco Electronic Hi-Fi.
A superb, top-ranking belt-driven
transcription turntable. 16-pole
synchronous motor, illuminated strobe,
dampened spring suspension and
anti-skating device. As precise as a
Swiss watch.
Model L65
The L65 Lenco Automatic belt-driven
Hi-Fi turntable. Light aluminium tone
arm. After selection of record diameter,
tone arm lowers itself onto the record.
After playing, it returns itself to tone
arm rest. Viscously dampened suspen¬
sion. A high quality instrument for
excellent reproduction.
Model L60
The L60 turntable, precision engineered
for great sound reproductonl Manual
operation, but with all other advanced
features of the L65. The L60 ... the way to
get renowned sound reproduction at a
moderate price.
PHOTIMPORT
MELBOURNE ADELAIDE BRISBANE PERTH SYDNEY
For descriptive literature and specifications, send a 30 cent stamp to
Qualitron Industries Division of Photimport (Australia) Pty. Ltd.
Head Office: 69 Nicholson Street, East Brunswick, Vic. 3057 Australia. Telephone: 3806922
PA10L
22
ELECTRONICS Australia, December, 1976
HIFI REVIEWS
New electret mics. &
accessories from JVC
Over the past few years, the quality of microphones
within the price reach of amateur recordists has
improved tremendously, making possible record¬
ings which do not sound all that different from the
professional product. Typical of the new generation
of microphones for the advanced enthusiast are two
recently announced by JVC Nivico.
Above , the M-201 stereo electret microphone and , below , the
components which make up the M-201 directional monosys¬
tem. Both come in a carrying case lined with moulded foam.
Designated as types M-201 and M510,
both are electret capacitor types, with
inbuilt battery-powered preamplifiers,
producting an output impedance of 600
ohms.
The M-201 should be particularly
attractive to those who like to take a
stereo tape recorder along to organ
society meetings and other such groups.
It is a very attractively finished unit, with
a mesh-enclosed head about 80mm wide
containing two microphone capsules,
each providing 120-degree cardioid
directional pattern orientated about 45
degrees to either side of centre front.
Together, the two capsules provide
excellent stereo definition, while retain¬
ing good frontal sensitivity. Both are sub¬
stantially protected by the housing from
the worst effects of wind noise.
The barrel, or handle, about 30mm
diameter and 160mm long, contains the
preamplifier, a 1.5V cell for the power
supply, an off-on music-speech switch, a
switched -10dB pad to cope with
overload situations, and the cable ter¬
mination.
JVC quote the frequency response as
40-18, 000Hz, the published curve look¬
ing commendably flat with only minor
"squiggles" between +1 and — 4dB from
100Hz up. Below 100Hz, the response
drops another 2dB to -6dB at 25Hz. On
the speech position, the response is cut
by about 4dB at 100Hz and by up to 8dB
at the very bottom end.
The sensitivity is quoted as — 71 dB (OdB
= IV/ubar) or — 81dB with the attenua¬
tor and pad switched on. Signal/noise
ratio is 47dB or better, wind noise 50dB
SPL (music) or 41dB SPL (speech), and
maximum input sound pressure level
(pad on) 133dB.
Battery drain is 0.3mA or less, giving a
battery life, with a high performance bat¬
tery, of about 15,000 hours.
Attracted by the general appearance
and finish of the M-201, we set it up in
a home situation, plugged into a good
quality cassette recorder. For a sound
source, we used a pair of high quality
loudspeakers, placed on either side of
the mic. about 4ft away— not too close,
but not so far away as to invite too
obvious intrusion of room acoustics.
Thus set up, we proceeded to record a
mixture of orchestral, instrumental and
organ, with natural voice announce¬
ments from left-centre-right.
Played back, the sound was the best
we have yet heard under these
conditions— a living room, domestic
loudspeakers and a non-professional
microphone. Apart from a slight room
echo around 150Hz, the response
sounded wide and clean, with the tran¬
sients from acoustic guitar sounding par¬
ticularly impressive. All told, the test held
a strong promise that the M-201 would
give an excellent account of itself in a live
music situation.
Retail price of the M-201 is $42.00
including tax. It comes packed in com¬
pliant foam in a neat carrying case.
The M-510 is a more specialised multi¬
purpose unit intended for advanced
amateur through to semi-professional
applications. A mono unit, it is really two
microphones in one package— or at least
it comprises a common amplifier/cable
body, to which can be attached either of
two heads, one giving a normal uni¬
directional cardioid pattern, the other a
highly directional pattern. Windshields
are provided, which can be slipped over
either when the microphone is being
used out of doors or under very close
speaking conditions.
Because of lack of time, we did not
have opportunity to test the M-510 in the
same way as the M-201 but, from the
literature, it would appear that the cap¬
sule and electronics are basically very
similar. Thus, the shorter uni-directional
capsule is credited with virtually the
same frequency response and pickup
pattern, marginally better signal/noise
ratio and better rejection of wind and
breath noises. In the "speech" position,
the cut in bass response is about 2dB
deeper. Sensitivity is the same.
For the super-directional capsule, the
lobe is much narrower, the curves
indicating a discrimination of at least
10dB front lobe over the 90-degree
response, even across the low frequency
range; above 300Hz, the ratio builds to
an average of better than 15dB. Response
below 2000Hz is virtually flat, with a
slightly rising characteristic up to and
beyond 10,000Hz. Sensitivity is quoted as
— 68dB for the frontal lobe.
Experience has shown that the M-510,
in its super-directional mode, is very suit¬
able for video taping activities where it
is desired to keep the microphone out
of the picture. Retail price of the M-510
is $139.95 including tax, and complete
with carrying case.
JVC are also marketing a variety of
accessories to go with their micro¬
phones, including a parabolic sound
reflector, 6-channel mixer, extension
cables, microphone stands and boom,
spring suspension cradle, support for a
stereo pair, &c.
For further information: Hagemeyer
(A'Asia) B. V., 59 Anzac Parade, Kensing¬
ton, NSW.
ELECTRONICS Australia. December, 1976
23
Top Disc Cutting Studios,
like The Mastering Lab,
rely on Stanton's 681-Calibration
Standard in their Operations.
Not everyone who plays records needs the Stanton Calibration
Standard cartridge, but everyone who makes records does!
At The Mastering Lab, one of the world’s leading independent
disc mastering facilities, the Stanton 681 Triple-E is the measuring
standard which determines whether a “cut” survives or perishes
into oblivion.
A recording lathe operator needs the most accurate playback
possible, and his constant comparing of lacquer discs to their
original source enables him to objectively select the most faithful
cartridge. No amount of laboratory testing can reveal true musical
accuracy. This accuracy is why the Stanton 681 Series is the
choice of leading studios.
When Mike Reese, principal disc cutter at The Mastering Lab,
plays back test cuts, he is checking the calibration of the cutting
channel, the cutter head, cutting stylus, and the lacquer disc. The
most stringent test of all, the evaluation of direct to disc record¬
ings, requires an absolutely reliable playback cartridge ... the 681
Triple-E.
All Stanton Calibration Standard cartridges are guaranteed to
meet specification within exacting limits. Their warranty, an indi¬
vidual calibration test result, comes packed with each unit. For the
technological needs of the recording and broadcast industries,
and for the fullest enjoyment of home entertainment, you can rely
on the professional quality of Stanton products.
LER 146
Sole Australian Distributors:
LEROYA IIMPUSTRIESltd _
Head Office: 156 Railway Pde., Leederville, Western Australia 6007. Ph. 81 2930.
N.S.W. Office: 1 00 Walker St., North Sydney 2060. Phone 922 4037.
VICTORIA Office: 1 03 Pelham St., Carlton 3053. Phone 347 7620
Available at quality conscious Hi-Fi dealers throughout Australia '
24
ELECTRONICS Australia, December, 1976
HIFI REVIEWS
Luxor 9341 automatic turntable
Products produced in Europe often employ unconventional design con¬
cepts. So it is with the Luxor 9341, which is produced in Sweden.
It provides fully automatic or manual operation and is most unusual
in the method of providing these automatic functions.
The Luxor 9341 has a compact base
and tinted cover with dimensions 407 x
150 x 345mm. An extra 65mm is required
at the rear of the unit to allow the cover
to open to the fully upright position.
Hinges of the tinted cover are friction
loaded to allow it to stay open in any
position. The cover can also be com¬
pletely removed from the base if
desired.
A very compliant suspension is used to
isolate the turntable chassis from heavy
floor vibrations and from acoustic feed¬
back. However, we feel that the sus¬
pension would be improved by the
incorporation of damping. As it is, it
tends to wobble around when the con¬
trols are operated. We also noted that
the suspension had sagged a little at the
rear, which may have been the result of
rough transport.
The dynamically balanced arm has a
decoupled counterweight and a sliding
weight to set the stylus tracking force.
The headshell is not removable. Instead,
it has a slide-out plastic carrier which has
12.7mm mounting centres but no adjust¬
ment for stylus overhang.
Anti-skating force is applied by a
spring mechanism operated by a calibra¬
ted dial. There are scales for conical and
elliptical styli. The cartridge fitted to the
arm was a Shure M75MB type 2. The
instruction booklet does not state
whether this cartridge uses a conical or
elliptical stylus, so we used the lower
anti-skating setting for conical stylus.
Surprisingly, the platter itself is a steel
pressing. This has the advantage of giving
a good flywheel effect but the disadvan¬
tage of interacting with the field of many
magnetic cartridges to effectively
increase the tracking weight.
Removing the steel platter reveals a
machined aluminium sub-turntable
which is driven by a small diameter idler.
The idler, in turn, is belt-driven by a
12-pole synchronous motor. The idler is
automatically engaged when the motor
starts by a cog mechanism which is
driven by the idler. This is a strange sys¬
tem and we wonder why Luxor did not
opt for a simpler belt drive. This must
presumably produce less rumble than
the idler/cog mechanism.
Speed change from 33 to 45 rpm is
accomplished by electrical rather than
mechanical means. A two-core mains
cord and three-pin plug was fitted, so
earthing was via the signal cable braids.
This is not recommended in Australia.
The most unusual feature of the Luxor
turntable is the arm set-down and return
mechanism. This is a spring mechanism
which is loaded by the on/off/lift/lower
control, which complements the disc
size selector in setting the operating
mode. Two disc sizes can be selected,
30cm and 17cm (corresponds to 12 and
7-inch sizes).
The arm can be made to leave the rest,
position the stylus over the edge of the
record and then gently lower. At the end
of play, the arm returns to rest.
Since the lift/lower lever loads the
spring mechanism, its action is very
heavy when initiating the play cycle. For
subsequent use of the cueing facility, the
lever is light in action. As another
sidelight, the arm mechanism can be
disengaged by moving the disc size
selector to M. This also disengages the
arm trip sensor, but does not appear to
effect a reduction in horizontal drag of
the arm.
Wow and flutter of the Luxor 9341 is
quoted at .05% according to DIN 45507
while rumble is rated at 62dB according
to DIN 45539. We measured wow and
flutter at about 0.15% which is a credit¬
able result, but we were unable to obtain
a particularly good result for rumble.
In operation, we found the arm
mechanism sluggish and reluctant to
work at all when 30 cm discs were
selected. This latter fault appeared to be
due to maladjustment of the height of the
lowering device.
In other respects, the Luxor is satisfac¬
tory. It is physically quiet in operation
and its suspension appears to work well
in preventing acoustic feedback. The
Shur$ cartridge performed well although
we did not take measurements.
Recommended retail price of the
Luxor 9341 turntable, complete with cart¬
ridge, is $248. Further information and
demonstration can be obtained from the
Australian distributors for Luxor
products, O.B.C. (Imports) Pty Ltd, 1396
Malvern Road, Tooronga, Victoria.
(L.D.S.)
ELECTRONICS Australia, December, 1976
25
or for $ 1.80 by mail order from
"Electronics Australia", P.O. Box 163
BEACONSF/ELD 2014.
$1.20
from your local
newsagent.
THE NEW Electronics Australia
YEAR BOOK
• The big push for CB radio in Australia.
• Optical fibres — the new look in
communications.
• Bush wireless in 1927— by
Rev. John Flynn
• Digital wind speed and
direction indicator.
• Build your own 250W music speaker.
PLUS
27 pages of valuable reference
data. Records to buy for your
collection. Hifi — amateurs —
DX— & much more.
Uncontrolled soldering temperatures
may have been adequate in the valve
and socket era, but today's solid-state
devices and printed circuits are easily
degraded by excess heat. This
controlled-temperature soldering
equipment protects your circuits . . .
and your reputation.
ADCOLA PRODUCTS
Melbourne, 848 3777. Sydney, 709 5293.
Brisbane, 52 3166. Adelaide, 42 6655.
Hobart, 34 2233. Launceston, 31 2511.
Perth, 815500
Non-destructive
soldering
THERMATIC
Mains voltage. Variable, electronic
feedback temperature control.
Solid-state sensing and switching.
Three times the heating power of
conventional tools for fast heat-up
and heavy duty soldering.
For less critical applications, the
DUOTEMP idles on half-wave AC at
the recommended soldering temperature.
Converts to full-wave, doubling power
for long sequences or heavy duty
soldering.
For more critical applications, the ECT
series low voltage soldering stations pro¬
vide complete safety, zero tip potential,
and accurate, dial-selected, infinitely
variable temperature control.
26
ELECTRONICS Australia, December, 1976
HIFI REVIEWS
Magnetic cartridges from National Panasonic
National Panasonic has released a range of four moving-magnet car¬
tridges onto the Australian market. They are sold complete with
headshell and storage holder, and every cartridge is accompanied by
its individual frequency response graph.
Most magnetic cartridges, especially
those in the higher price ranges, are
supplied in a fancy presentation case
which is about as useful as a spare groom
at a wedding. Not so with National
Panasonic, which has taken a different
approach.
First, each cartridge is fitted into a stan¬
dard headshell with the EIA locking
collar, ready to use with the large
majority of turntables. Second, the plas¬
tic box with its swing-out lid functions as
a storage compartment for the head-
shell-cum-cartridge. This is a really useful
idea since many keen enthusiasts have
several cartridges mounted in headshells
but no proper way of storing them
safely.
The headshell storage compartment
has space in the rear to store the supplied
accessories— extra hardware, screw¬
driver and a small phial of stylus cleaning
fluid.
There is one problem with the
supplied headshell, however. It is. the
same as that fitted to Technics turntables
and has no adjustment for stylus over¬
hang. A small change to the headshell
would make this possible.
Another refinement would be to fit the
cartridges with flip-down stylus guards,
rather than use the clip-on types
supplied. Clip-on stylus guards are too
easily lost, and can cause stylus damage
when they are being removed.
There are two basic cartridges, the
EPC-205 series which has three variants
and the lower-priced EPC-270C-II. All
have 12.7mm mounting centres, colour-
coded terminals and removable stylus
assemblies.
The three variants are the EPC-205C-
IIS, EPC-205C-IIL and EPC-205C-IIH, The
"S" is the standard model of the series
with an output of 0.7mV/cm/sec. The
" L " type is a low impedance version
which has the advantage of not being
affected by load impedance variations or
high values of shunt capacitance. The
compromise is a lower output voltage of
0.4mV/cm/sec.
The "H" version has the same
impedance characteristic as the "S" ver¬
sion but a different stylus assembly which
enables double the output voltage to be
obtained, 1 .4mV/cm/sec. The stylus
assemblies of these two variants are
interchangeable. The styli are elliptical,
0.2 x 0.7mil.
Apart from impedance characteristics,
performance specifications for the
EPC-205 series are identical. Frequency
response is rated within ±2dB from
10Hz to 25kHz. Best results for the "S"
and "H" versions are obtained with a
load impedance of 50k and a cable
capacitance of lOOpF.
Tracking force for the trio is 1.25g
±0.25g. Channel separation at 1kHz is
quoted at 25dB or more and 20dB or
more at 10kHz.
m
tracked the +15dB test track on CBS STR
110 and the +12dB drum test track on
W&G 25/2434. Separation at 1 kHz is a lit¬
tle over 20dB ranging to a minimum of
about 12dB at 12kHz.
The lower priced model 270C-II was
also flat within ±2dB from 20Hz to
20kHz. The waveform showed some
irregularities in the 8kHz region, while
the square wave response showed some
well damped ringing. Tracking perform¬
ance was slightly better than for the 205C
series but the higher tracking force
should be taken into account. Separation
between channels was excellent, with
better than 40dB at 1 kHz and better than
30dB over most of the range.,
National Panasonic
MW udw !N/w»eoA,*N*c€
W sao&o-g
STEREO CARTRIDGE
P»***ONP
Each cartridge is fitted in a headshell and supplied with a storage container.
Specifications for the lower-priced
model EPC-270C-II are as follows:
Frequency response from 20Hz to 15kHz
within ± 2dB; channel separation 25dB or
more at 1kHz; tracking force 1.75g
±0.25g. The stylus is elliptical, 0.3 x
0.7mil.
Our tests revealed that the perfor¬
mances were strikingly identical. This
indicates tight quality control. Frequency
response was within ±2dB over the
range 20Hz to 20kHz as tested on the
CBS STR-100 disc. Waveform on sine-
waves was generally good, while square
wave response was very good with little
trace of overshoot or ringing. All three
Clearly, all four cartridges are fine per¬
formers. The 205C series allow a number
of useful compromises. For most ampli¬
fiers which have plenty of input overload
margin, the "H" version would give a
useful improvement in signal-to-noise
ratio. The 270C-II model will appeal to
those on a budget.
Recommended retail prices for each of
the EPC-205C series is $67.50 while the
EPC-270C-II retails-for $35. Further infor¬
mation can be obtained from high fidelity
retailers or from the Australian distribu¬
tors for National Panasonic, Haco Dis¬
tributing Agencies Pty Ltd, 57-69 Anzac
Parade, Kensington, NSW. (L.D.S.)
27 '
ELECTRONICS Australia, December, 1976
8.00am “Start the day with a heavy earth
connection on the emergency power plant.
Need a 130 watt iron. My Superspeed's got
that and more. Just as well, the workshop’s
400 yards away”.
9.15am “Call from No. 2 Moulding
Shop. Ran some temporary leads involving
both tag joints and Printed Circuit Board
(P.C.B.) connections. The Scope Minispeed
handled the lot".
10.55am The V.D.U. in the process
control room is playing up. Replacing
miniature resistors on a P.C.B. is, ideally, the
job for a temperature controlled 60w iron but
my Scope Minispeed did the job and did
it well.
"WITHOUT MY SCOPE IRONS
I RECKON I'D NEED A 25 HR. DAY."
1 1 .1 5am “Fix the speaker leads in the
canteen P.A. Need a 30-40 watt iron, but my
Scope Minispeed did the job”.
1.30pm “Resolder a 7/036 earth to sheet
metal — LP gas flame would work, but too
much risk of heat damage to PVC cable. The
Superspeed iron produced its full 150 watts
and did the job”.
2.15pm “Fred borrowed my Minispeed
to tackle an open circuit on the fork lift's
headlights. He permanently soldered the
wires to the terminal block, and used the
Mini’s 75 watts to do it”.
2.17pm “Tag soldering in the workshop
and a desolder job on a P.C.B. Using the
Minispeed saves swopping between
conventional 60 watt and 25 watt irons”.
3.58pm “Emergency in shop six. I used
my Minispeed to unsweat the leads of the
main heater control circuit and then desolder
the pyrometer circuit on the P.C.B. One iron,
two different jobs”.
4.18pm “This wiring’s a real birds nest.
Passed through the wires with the Minispeed
stone cold, desoldered the three joints, let the
iron cool down, then withdrew through the
PVC insulation. The 5 second heat up and low
tip mass let’s me do this”.
Scope soldering irons save time three
important ways:
1. Versatility.
One Scope iron replaces several conventional
irons because it can tackle a wide range of soldering
problems, from integrated circuits and printed circuit
boards to heavy earth and chassis connections.
You don’t have to swap irons half-way through
the job. Both the Minispeed and the Superspeed
function as 20-30 watt irons, and then within seconds
and a touch of the finger switch, you get increased heat
output to increase the Minispeed to 75 watts, and the
2. Speed.
Five seconds gets both irons ready for work, and
they cool down quickly as well. When you encounter a
heat sink you want an iron that can make up the heat
loss instantly and maintain good soldering temperature.
Result, the job’s done fast and you can move onto
the next.
^ (A) Scope Cordless. 60W.
Designed for working where no power is
available or during temporary failure. It’s powered by
two rechargeable Nicad cells with the capacity to solder
between 100 and 200 typical electronic connections
before overnight recharging.
(B) Scope 12V Hobby Iron.
This versatile iron is designed to work within
6 metres of your car battery.
3. Safety.
Scope irons are isolated from the mains. The
special isolation transformer lets you work on live
equipment with a higher degree of safety than a
conventional iron.
(C) Scope Vibroscope.
This electric pencil allows for permanent writing
on all metals. Valuable in an engineering store
identifying metal tools, dating and naming parts,
inscribing trophies.
The Scope range of products is designed to
deliver efficiency and convenience.
Consider the advantages of
these products.
For enquiries and further information on the
Scope range of products contact: Scope Laboratories,
93 Matthews Avenue, Airport West, Melbourne, 3042.
SCOPE
RIGHT IRON FOR THE RIGHT JOB.
SL1
Light beam communications in the 1980s
The optical fibre
revolution — Part i
Communications via light beams and glass fibres— the concept
sounds like science fiction to most people. But optical fibre com¬
munications are poised to become reality, and will revolutionise
communications by the end of the century. The promise is a com¬
munications network made up of hair-fine glass fibres glowing with
laser light, each capable of simultaneously carrying 20 channels
of colour TV or 1 0,000 telephone conversations.
The familiar image of the soprano
whose high notes broke a glass is about
to reverse itself. Miles and miles of glass
soon may be the major ingredient in
breaking the world's communications
logjam.
Within the next five years, modern
technology hopes to begin solving many
of the world's communications problems
by using revolutionary new transmission
media— light and glass— to achieve a via¬
ble system of optical communications.
Glass tubes, lasers, integrated optics,
lenses and prisms — items more
appropriate to chemists, physicists and
optometrists— soon will replace parts of
the familiar network of copper cable and
electronic circuitry that plays such a vital
role in communications today.
Optical communications can be as
much as 1 ,000 times faster than electronic
communications. The optical fibres that
are the basis for this new type of com¬
munication can hold 10,000 times more
information than a like amount of copper
wire or cable.
A revolution is now under way, trig¬
gered by significant breakthroughs in
these non-conventional communications
techniques, and by the mounting tie-ups
and congestion that have almost crippled
the conventional communications net¬
Corning research scientist Dr Frank Thiel demonstrates the practical use of optical
fibre waveguides. Here a camera video signal is carried by an 1,100 ft long bundle
of glass fibres coupled to a TV receiver.
by JON FREDRIC
works in the United States. The conges¬
tion results from overcrowded telephone
lines that transmit all kinds of informa¬
tion, ranging from conversations to the
transmission of pictures, and the
exchange of data by computers.
One oversimplified solution would be
to add more telephone lines. But this
runs foul of space limitations —
particularly in cities where conduits in
buildings and under the streets are
already overcrowded. There just isn't
that much room for more lines.
The only realistic solution, then, is a
communications system carrying a con¬
siderably greater number of messages
within a smaller amount of space.
Sound impossible? Not any more!
Scientists have long known that light
offers the fastest potential means of com¬
munication and has thousands of times
the capacity of wire cables or even short¬
wave radio.
As early as 1870, the famous British
physicist John Tyndall demonstrated the
potential of light to the members of the
Royal Society of England. He showed
that part of the light illuminating the
inside of a container of water was guided
along a stream of the liquid flowing
through a hole in the vessel's side. That
was the first recorded demonstration of
light transmission along a dielectric guide
by total internal reflection.
In recent decades, the development of
the laser provided the largest single
boost to man's dream of communicating
on a beam of light. However, researchers
soon learned that sending "naked" laser
beams through space wouldn't solve
mass communications problems. The
wavelengths used by these light beams
30
ELECTRONICS Australia, December, 1976
are so short that atmospheric particles
caused the signals to break up.
To solve this problem, researchers
looked for ways to ''pipe" the light
beams from transmitter to receiver.
It wasn't until the 1950s that the idea
of a hair-thin cylindrical core of glass— a
pipe that carries light beams— evolved,
according to Tingye Li and Enrique Mar-
catili of Bell Telephone Laboratories,
American Telephone and Telegraph's AT
& T) research arm.
At the same time, Bell Labs developed
a way to make these fibres by pulling a
preformed glass rod through an opaque
tube that had been softened by heat in
an oven. The rod forms the core and the
tube forms the cladding that prevents
light from escaping the "pipe".
Soon these fibres were being grouped
in "coherent bundles"— flexible bundles
that transmit high-resolution images.
"From this point," say Marcatili and Li,
"the number of inventions based on fibre
optics mushroomed: faceplates for TV
camera tubes, medical instruments,
image dissectors for high-speed photo¬
graphy, and many more."
International Telephone and
Telegraph (ITT) scientists in England
were the first to explore fibre optics tech¬
nology for long-distance communica¬
tions. In the mid-1950s, a team headed
by Dr Charles Kao, a native of mainland
China, recognized that a technique
employing pure glass and long-lived
lasers could be developed to permit
long-distance communications. The
team subsequently began experiments.
According to Dr Kao, the scientists
demonstrated an optical fibre system
that could simultaneously carry 1,400
voice conversations, or 17 picturephone
conversations. Eventually they were able
to transmit full-colour TV pictures over
the hair-fine fibre with excellent results.
Today Dr Kao works for the ITT Fiber
Optics Laboratory in Roanoke, Virginia.
The most promising light pipe was the
fibre optic waveguide, which operates
on the principle of total internal reflec¬
tion of light. Each light pipe has a centre
strand of glass surrounded by an outer
glass cladding, which prevents light in the
centre strand from escaping. Light enter¬
ing the core glass and striking the outside
cladding is reflected within the inner core
repeatedly through the entire length of
the fibre.
Early studies showed that, in order to
be economically practical, waveguides
(as these light pipes are now called)
would have to transmit light signals with
very low light loss. This loss of light in
transit is expressed in decibels per
kilometre, an expression of the ratio of
the energy input to the energy output.
"From the start," says W. Bart
Bielawski, of Corning Glass Works, "loss
levels of 20dB/km were accepted by
scientists in the field as the goal to be
achieved," since that level meets the
standards of today's telecommunications
systems. It was also considered sufficient
to tip the economic scales in favour of
optical waveguides.
'That goal was surpassed in August
1972, when Corning achieved losses of
as low as 4dB/km," he said. "But in June
1973, Corning reached the ultimate goal
of 2dB/km," which finally made glass
fibres economically attractive for use in
long-distance communications.
Today there are two types of low-loss
optical waveguides. The first-invented,
better understood, and more glamorous
is the single-mode waveguide. It has a
tiny glass core that transmits light from
a laser.
Its principal advantage is that it
provides the highest capacity which gives
it most promise for long-distance inter¬
city communications. But its principal
disadvantage is that the laser that must
be used with it has yet to be perfected.
Ihe other type, called "multimode,"
An optical glass fibre cable developed by
ITT (centre) contrasted with conven¬
tional copper cables. The six-fibre glass
cable has more communications -
carrying capacity than the two larger
cables combined.
Dr Charles Kao , the ITT scientist who first
suggested using glass fibres for long¬
distance communications.
has a large optical-glass core that can
carry types of conventional light.
Because it is simpler to put together, it
is expected to find more immediate use
in shorter-range inner-city networks.
The main advantage here is that power
requirements for the light sources are
significantly less than those required for
laser-based systems. In fact, the light
sources for multimode fibres can be
powered from the same supply used to
power any associated electronic cir¬
cuitry.
Flow does optical communication
work?
In a recent telephone demonstration
of optical communications by AT & T, the
sound waves entering a telephone
microphone were converted into elec¬
trical signals. These signals were then
passed through an encoder, which con¬
verted them into electrical pulses that
switched the light beam on and off, inter¬
rupting the beam being sent through to
the end of the fibre tube. The signal is
thus transmitted along the fibre as a
series of light pulses, rather like Morse
code dots and dashes.
At the end of the fibre tube, the light
pulses were fed into a receiver and
thence to a decoder for translation back
into an electrical signal. This signal was
used to drive the receiver diaphragm to
reproduce the original sound waves.
So the process is practical and works
quite well, but there are still problems to
overcome before the system can be
made available to the nation's con¬
sumers. Much work must be done to
develop light sources and intermediate
circuit parts that can connect the glass
tubes and amplify the signals they carry.
The development of lasers sired the
realization that optical communications
might be feasible. It's ironic that further
laser development has fallen behind the
development of glass fibres, which
experienced several major break¬
throughs within recent years.
Nevertheless, researchers at many
leading laboratories-notably Bell
Laboratories (AT & T's research arm),
International Telephone and Telegraph
Corporation, and Corning Glass Works-
are concentrating their efforts on
developing the laser as a prime light
source for optical communication.
Lasers provide absolutely pure beams
of light that are ideally suited for optical
communications. The combination of
laser light and optical waveguides holds
the greatest promise in terms of com¬
munications capacity.
Dozens of different lasers have been
developed for other uses, and Bell Labs
and others have devised new, smaller
lasers at suitable frequencies. Yet none
yet have the long life and reliability
required for a communications system.
But the appearance of glass fibres that
can carry laser light long distances is now
spurring development. It's only a matter
of time before the laser catches up.
(To be continued)
ELECTRONICS Australia, December, 1976
31
0
< t
News Highlights
On-line computer analyses lung behaviour
A research group in the University of
New South Wales School of Medicine
has developed a unique system of "on¬
line" study of the mechanical behaviour
of the lungs. This is believed to be the
first such system fully operational in the
world.
Working at Prince Henry Hospital,
Associate Professor John (H.J.H.)
Colebatch has successfully linked
patients and a small computer to provide
vital data on the patients' lungs which
reflect their internal structure. The new
system reduces the data almost instantly
into graphs which are proving highly
valuable in diagnosis, treatment and
research on respiratory ailments.
Previous manual systems were so slow
that a week could elapse before the
results of tests on a patient could be
finally analysed, rendering the system
impractical for clinical situations.
There are two main aspects of the
mechanical behaviour of the lungs—
elastic behaviour which reflects the
properties of lung tissue, and conductive
behaviour which reflects the number,
size and distensibility of the airways. By
making measurements that reflect the
elastic and conductive properties separa¬
tely it is possible to distinguish between,
for instance, emphysema (tissue break¬
down) and bronchial diseases, even
when the distinction is not possible on
routine clinical and X-ray examination.
Such a distinction is important because
it influences treatment.
The medical value of the new system
is now being realised on a routine basis
at Prince Henry Hospital, one of the
University's teaching hospitals. The
structural changes in diseased lungs can
now be deduced from tests taking about
an hour. Previously, doctors could only
obtain such detailed information too
late— through autopsies after death!
In addition to organising regular
clinical applications of the system,
Professor Colebatch is engaged in a
study of the effects of ageing on the
lungs. His group has already examined
more than 80 healthy subjects, some of
whom were provided by the Royal Aus¬
tralian Navy.
Solar observations may
aid weather predictions
A newly developed sunlight filter is
allowing astronomers at Lockheed's
Research Laboratory in Palo Alto, Califor¬
nia, to more accurately study the Sun in
hopes of some day predicting the effects
of solar flares, sunspots, and promin¬
ences on Earth weather.
The filter was designed and built by
Lockheed and recently was selected by
Industrial Research magazine as one of
the 100 most significant new technical
products of 1976. By excluding bright
ordinary sunlight, the filter allows the
detection of solar activity that is normally
too faint to observe. The filter is tunable
and can separate wavelengths that differ
in length by less than one-billionth of an
inch.
Although it is still too early to make any
specific weather predictions from these
solar phenomena, Dr Alan Title, senior
member of Lockheed's Solar Observa¬
tory, says there is mounting evidence that
short-term and long-term weather trends
have a definite correlation with unusual
solar activity.
Current research is aimed at under¬
standing the nature of the sunspots,
flares, and prominences— how they are
formed; why they are formed; and how
their effects are transmitted from the Sun.
Once these questions are answered and
understood, data from the occurrences
can be used in the generation of large-
scale weather prediction models.
Postgraduate course
in digital control
The Footscray Institute of Technology
has announced the introduction of a
Postgraduate Diploma course in Digital
Control. The course, commencing
February 1977, covers two years part-
time.
The course has been designed to cater
for the increasing needs of industry for
engineers capable of applying the latest
minicomputers, microprocessors and
sub-systems to specific on-line control
and data acquisition systems. Special
emphasis will be placed on practical
experience and actual industrial applica¬
tions.
Entrance requirements are a degree in
Electrical, Electronic or Communications
Engineering. Persons with a diploma in
the above fields or with alternative
professional qualifications, and who
have relevant professional experience,
may also be considered for admission.
Further details from the Footscray
Institute of Technology, Department of
Electrical and Electronic Engineering, PO
Box 64, Footscray, Victoria 3011.
Telephone 689 3400.
ELECTRONICS Australia, December, 1976
32
Dick Smith opens two new stores
Dick Smith's new Brisbane store.
Dick Smith's new Melbourne store
Dick Smith Electronics has opened
two new stores; one each in Brisbane and
Melbourne. The group now has five
stores down the eastern coast of Aus¬
tralia, as well as many dealers appointed
to handle Dick Smith merchandise right
across the mainland and Tasmania.
The Brisbane store is in suburban
Buranda, close to the Woolloongabba
Cricket Ground. The address of the store
is 166 Logan Road, Buranda. Logan road
forms part of the Pacific Highway, the
busy main road north out of the city, and
puts the store in a prime location.
The Melbourne store is east of the city
in the 'retail electronics centre', Rich¬
mond. This store is just a stone's throw
from the Yarra River, and it too is in a
prime location. The address is 656 Bridge
Road, Richmond.
Both stores have department-store
type layouts, with merchandise displayed
in airy, well-lit sections. Both stores carry
the same wide range as the 3 Sydney
stores, a range which has made Dick
Smith Electronics famous throughout
Australia.
Ferranti develops fast
1 6-bit microprocessor
Ferranti UK has announced the release
of the F100-L 16-bit microprocessor, the
first microprocessor to be wholly de¬
signed, developed and manufactured in
Europe. The new device was sponsored
by the UK Ministry of Defence.
Produced using the Ferranti CDI
process, the F100-L chip features high
performance. Typical instruction times
are 3 to 4 microseconds. It can also
handle up to 32,000 16-bit words of fast
semiconductor or core memory, and has
advanced real time interrupt facilities.
Power dissipation is less than 375mW.
The F100-L is fully supported by
development software and a library of
application programs which assist the
user in programming his own system.
Programs are currently developed on
"host" computers. However, further
software will be released in 1977 to allow
programs to be developed on the F100-L
itself.
Japan unveils new broadcasting technologies
The japan Broadcasting Corporation
(NHK) recently threw open the doors of
its Technical Research Laboratories to
the public for its annual display of tech¬
nical achievements. Among the crowd at
the display, held last june, were: a
30-inch wide screen colour TV display
with 1,125 scanning lines, a gas-discharge
colour TV panel, and a television ghost
suppression system employing a charge-
coupled device (CCD).
A second television ghost suppressor
was also on show, this employing
two variable directionality receiving
antennas and a simple adjustment
process. The CCD method has not yet
been practically applied, although its
future looks promising.
Colour TV cameras on show demon¬
strated the rapid progress towards LSI,
resulting in reduced camera size,
reduced power consumption, and
greater reliability. The results of studies
on standardising camera and VTR colour
tones by means of a microcomputer
were also made available.
Award for Plessey timber stress grading machine
The Australian developed and
manufactured Computermatic timber
stress grading machine has earned
another international award for its
manufacturer, Plessey Australia.
The latest award-a diploma gained at
the Australian Trade Display in
Moscow— follows a gold medal for tech¬
nical innovation won by the machine at
the Leipzig Spring Fair earlier this year.
The machine, which provides an
accurate, reliable and non-destructive
means of sorting timber into strength
grades, has gained widespread accept¬
ance overseas, particularly in the United
Kingdom and Sweden where
mechanically graded timber is increas¬
ingly specified for housing construction.
To date 85 Computermatics have been
manufactured by Plessey in Sydney and
68 of these been exported, including two
for installation in Russian sawmills.
The Computermatic determines the
strength of square edged timber by sub¬
jecting it to a known load and automatic¬
ally measuring the degree of deflection.
The load applied does not damage the
timber, unlike so-called 'proof testing'
which involves applying a load close to
the breaking point of the timber.
TRONICS Australia, December, 1976
33
Motorola
announces
the high-current
low cost
35 A bridge
We don’t think anybody will admit coming
even close to the MDA 3500’s high-current,
low-cost 35 amp capability.
Like giving 10 extra amps current handling
at the 25 amp price. Plus 100 extra amps
surge-protection at the 25 amp price, and
super-efficient, 70 watt power dissipation at the
25 amp price.
Check these features: — 400 ampere surge
capability, electrically isolated base, fast
recovery availability on request, cost effective
in low current applications — and you’ll have
to admit our point — superior performance at
equal cost.
Stock now available from
CEMA DISTRIBUTORS
PTY LTD
21 Chandos Street
LEONARDS
— ,j Phone: 439-465f
"1-IH rjM
WOLLONGONG— MAf
MELBOURNE — CEMA . 877-531 1
BRISBANE— ELECTRONIC COMPONENTS . 371-5677
CANBERRA-CUSTOM SCIENTIFIC . 47-6 1 79
ADELAIDE— WILLARD CRABBE . 51-4713
PERTH-RESERVE ELECTRONICS . 87-1026
34
ELECTRONICS Australia, December, 1976
NEWS HIGHLIGHTS
Foot-controlled vehicle for the disabled
A foot control for a car— using the same
principle as Concorde's fly-by-wire elec¬
trical controls— is now on test in Britain.
It will make it possible for a severely dis¬
abled driver to have complete control of
the car using only one foot. Like Con¬
corde, it has duplicated control circuits
and a 'fail-safe' monitoring system.
This standard British Mini car is steered
by a small joystick operated by the
driver's left foot, which generates a signal
to an electrically-controlled servo system
controlling the steering, throttle or brake
as required. The prototype has been
developed by Britain's Transport and
Road Research Laboratory for the
University of Reading.
Two independent control channels are
used, with a third monitoring channel so
that in the event of a fault the vehicle can
be brought to a safe stop using the re¬
maining working channel. The standard
handbrake has been replaced by a
ratchet-action unit as used in heavy
goods vehicles.
Trials are in progress on the test track
of the technical reliability of the system.
Further tests will include manoeuvring in
traffic and use in normal operating condi¬
tions.
BBC seek £2m for traffic radio service
The successful trial operation of a new
traffic information broadcasting system
in Britain has resulted in an approach by
the BBC to the Government for a £2
million grant. The BBC wants to set up
a chain of 80 national stations, which
would continuously broadcast traffic
information and hopefully avoid the
major traffic jams that have occurred in
the past.
The system consists of a series of low-
powered radio transmitters together with
a small, low-cost receiver in each car. All
stations would broadcast on the same
frequency in the medium wave band,
and would have a range of about 20
miles. The receiver, costing around the
£7 mark would be wired into existing car |
radios in such a way that the broadcast
message would cut into any program the
driver might have chosen.
The receiver could also be wired to cut
into the music program from a cassette
player. However, the driver will be able
to switch off the traffic broadcast channel
if he so chooses.
GE to build super-battery — lOkW-hr goal
A $2.5 million contract for developing
a superbattery that could be used by
electric utilities for bulk-energy storage
has been awarded to the General Electric
Research and Development Center by
the US Electric Power Research Institute
(EPRI).
The 32-month effort-the largest
battery-research contract ever issued by
EPRI, the research arm of the electric
utility industry in the US— will comple¬
ment a parallel GE energy-storage
program launched several years ago.
The program's objective: to develop a
rechargeable sodium-sulphur storage
battery that potentially offers five times
more storage capacity per pound than a
standard lead-acid battery.
Under the EPRI contract, GE scientists
will seek to develop and construct a
sodium-sulphur unit about the size of a
file drawer, with a storage capacity of
Live sound.
Your
reference
and ours.
If you judge speakers by their ability to reproduce live
sounds ... KEF created the Reference Series for you.
Taking the latest advances in drive unit technology, and
applying the same uncompromising standards to enclosure
and driving network. Building on KEF experience in
professional monitors . . . applying radically new computer
evaluation techniques. With live sound the reference at
every stage. Result two compact systems, winning world
acclaim for accurate uncoloured quality even at high
sound pressure levels.
Model 104. Shelf or stand system. High power KEF
tweeter, mid-range unit and base drone ... all with
advanced laminated diaphragms that absorb colouration-
causing energy. High performance 6 element dividing
network with acoustic contour control.
Model 103. Bookshelf system with KEF tweeter and bass
driver on unique steel baffle that rotates to maintain
intended dispersion in any cabinet position. Latest driver
technology, plus high density anti-resonant enclosure
linings.
REFERENCE
SERIES
about ten kilowatt-hours.
Proposals are that large storage units
could be installed to take excess energy
during periods of low power demand
and permit the power authorities to run
power stations at optimum level, thus
saving fuel. During peak demand
periods, this stored energy could be
discharged into the system without the
need for extra generating capacity.
The new work sponsored by EPRI is
directed toward further increasing the |
lifetime of sodium-sulphur batteries by
improving certain components, par¬
ticularly the seals that secure the system.
It will lead to the construction of a 100-
kilowatt-hour battery module? Such a I
unit could be trucked to a distribution |
substation and become the basic buil¬
ding block of a utility battery system. GE
also expects to install and test a 5MW |
system by 1981 .
Distributed by Audioson International Pty. Ltd.
64 Winbourne Road,
Brookvale. N.S.W. 2100
Sydney Melbourne Adelaide
938 1186 329 6066 337 7000
Penh
25 9993
ELECTRONICS Australia, December. 1 976
35
I
NEWS HIGHLIGHTS
Wind tunnel for "hands-on" flight training
A new type of wind tunnel, developed
in Britain, enables trainees to 'fly' a model
aircraft so that many of the important fea¬
tures of aircraft behaviour during flight
can be accurately observed.
Unlike conventional wind tunnels, the
Flight Demonstration Wind Tunnel
incorporates a control column for adjust¬
ing the model aircraft's elevators, and a
throttle control for regulating the air
speed in the tunnel. By operating these
two controls, the trainee can 'fly' the
model— simulating acceleration along the
runway for take-off, control during flight,
and full landing procedure. It is also pos¬
sible to stall the model to study the rela¬
tionship between trim and speed.
The tunnel, however, is not limited to
visual demonstrations. The linkage sup¬
porting the model is attached to instru¬
mentation capable of measuring aircraft
trim, altitude, the influence of the centre
of gravity on stability, and lift force. The
effects of airstream can also be measured
using a smoke distributor which shows
the flow pattern past the model in normal
and stalled conditions.
AWA sells air navigation aid to Portugal
An Australian designed and manufac¬
tured radio beacon has been chosen for
a new air navigation installation at Por¬
tugal's Lisbon airport.
The beacon, a product of the Avionic
Systems Department of Amalgamated
Wireless (Australasia) Ltd, is the main
element in a contract awarded by the
Portuguese Government to the Decca
Navigator Company of Britain for the air¬
port installation.
The beacon is a Doppler VOR (very
high frequency omnirange) particularly
Burroughs to build
a “supercomputer”
US computer manufacturer Burroughs
recently announced that it intends build¬
ing a "supercomputer" to carry out the
solving of problems at present con¬
sidered too large for existing machines.
Basically, the machine will be an array
processor; that is a series of smaller com¬
puters operating in parallel on a large
problem divided into sections. It will be
so powerful that it will need one of the
company's largest conventional
machines to prepare and feed it with
information, and to collect the results.
Suggested applications are in
meteorology, space studies and logistics,
etc. The first machine is expected to be
running by the' end of 1978, and will be
programmed in Fortran.
A similar machine is also under con¬
sideration in Britain by International
Computer (ICL), which is awaiting
government support before going ahead
with the project. This machine, if built,
suited to airports and enroute locations
where radio signals are affected by
reflections from mountains, buildings
and other obstacles. VOR is an interna¬
tional standard medium range guidance
system providing bearing information to
aircraft.
AWA Doppler VOR beacons are
already operating at Kathmandu and
Pokhara in Nepal, at Biggin Hill near Lon¬
don, UK, and are being installed at Mers-
ing in Malaysia, and at 10 locations in
Australia'.
could be anything up to 100 times faster
than existing machines, according to the
type of problem.
Cable TV — via
optical glass fibres
Thirty-four thousand cable television
subscribers in the Hastings area of
England are believed to be the first in the
world to watch TV programs brought to
their receivers over strands of glass rather
than wire.
According to a recent press release
from Corning Glass Works (United
States), Rediffusion Limited of London
has been using a 1.427-kilometer length
of optical cable, inserted into its existing
network in place of metallic-conductor
cable, since March 1976.
The cable was manufactured by BICC
Telecommunication Cables Limited. It
contains two hair-thin strands of glass
made by Corning in the USA. Installation
was carried out by Rediffusion engineers,
and completed in just two days.
ELECTRONICS Australia, December, 1976
Where to hear
the 1812 Overture with
carinon, not corks.
N.S.W.
SYDNEY CITY
Douglas Hi Fi. Kent Hi Fi.
D.M.E. Hi Fi. Jnstrol Hi Fi.
EASTERN SUBURBS:
Woolloomooloo— Convoy Sound.
NORTH SHORE :
Chatswood— Autel Systems.
Crows Nest— Allied Hi Fi.
Gladesville— Hi Fi Hit.
Chatswood— Milversons.
Brookvale— Riverina Hi Fi.
WESTERN SUBURBS:
Fairfield— Bing Lee Electronics.
Summer Hill— Fidela Sound.
Parramatta & Westfield— Grammophone Shop.
Parramatta— Milversons. •
Parramatta & Bankstown— Miranda Hi Fi.
Concord— Sonata Music.
SOUTH
St. Peters— Dyna Stereo.
Miranda Fair— Miranda Hi Fi.
LIVERPOOL : Miranda Hi Fi.
WOLLONGONG: Sonata Hi Fi.
GOSFORD: Miranda Hi Fi.
NEWCASTLE : Ron Chapman Hi Fi.
Newcastle Hi Fi.
MAITLAND : Hunter Valley Electronics.
TAREE : Godwins Hi Fi.
LISMORE: Lismore Hi Fi. *
A.C.T.:
Pacific Stereo. Duratone Hi Fi.
VICTORIA:
MELBOURNE CITY:
Douglas Trading. Nat. Sound.
Allens Music. Southern Sound.
Instrol Hi Fi.
MELBOURNE SUBURBS:
Hawthorn— Tivoli Hi Fi.
Nth. Caulfield— Soundcraftsman.
Moofabbin— Southern Sound.
Mordialloc— Mordialloc Hi Fi.
—Denman Audio.
, Belmont— Belmont Stereo.
Warnambool— A. G. Smith.
QUEENSLAND:
BRISBANE CITY:
Reg Mills Stereo. Tel Air Electronics.
Stereo Supplies.
BRISBANE SUBURBS:
Redcliffe— Hi Fi Sales (Q'ld.) Pty. Ltd.
Ashgrove— Living Sound Centre.
Tingalpa— Todd Hi Fi.
Ipswich— Ipswich Hi Fi.
SOUTH AUSTRALIA:
ADELAIDE CITY:
Allans Music.
Challenge Hi Fi.
Hi Fi Acoustics.
ADELAIDE SUBURBS:
Blackwood— Blackwood Sound.
St. Peters — Sound Dynamics.
TASMANIA:
HOBART:
Quantum. United Electronics..
SUBURBS:
Burnie — Audio Services
WEST. AUSTRALIA:
PERTH:
Alberts Hi Fi.
Leslie Leonards.
Audio Centre.
Japan Hi Fi.
Or write to Auriema (A/asia) Pty. Ltd.
P.O. Box 604, Brookvale, N.S.W. 2100
Telephone 939 1900
36
When you dance around the room
can you hear aJl the music?
Some very heady stuff is bandied about
when it comes to discussing the pro's and
cons of various speakers.
All of it rather wonderful of course, but
invariably there’s one small catch.
Unless you stand practically right in front,
the sound you get will never be all that
clearly defined.
This of course brings us to our speakers.
The Epicure Tens.
Not only can you hear them in just about
any part of the room, but you can hear, very
clearly, every instrument that's meant to be
heard. Simply because they give near
hemispherical dispersion.
You’ll also find lower distortion in the mid¬
range, especially noticeable with voices.
( Due to a balanced, low-mass voice coil
assembly which is centred perfectly and
automatically by the use of a unique space-
age, ferro-fluidic liquid.)
While the concave air spring tweeter
produces nearly hemispherical dispersion
across most of the audible range .
The Epicure Tens also contain a rather
unique low-mass woofer.
This gives a smoother, more accurate^
bass, enabling you to hear
the individual bass instru¬
ments, andnot just the bass.
In fact so proud are we
of our speakers, we even
go so far as to give them a
ten year warranty.
And that's an awful lot of
dancing around any room.
EPICURE
AUR21
VWtctfer.
chromium!
New particle: TDK has developed a new particle called Super
Avilyn. It’s cobalt and ferric-oxide in a single layer. It is not the
same as so-called ‘cobalt-doped’ and ‘cobalt-energized’ tapes.
New performance: The superior high-end saturation of Super
Avilyn’s high-coercivity formulation (allowing it to take more
high frequency energy during recording), combined with its
compatibility with the Cr02 equalization (1 EC 70 microsecond
time constant) results in a simultaneous suppression of
high-end noise (for better S/N) and delivery of a flat response
curve with better highs.
SA’s performance exceeds even Cr02, which suffered from
reduced output in the middle and low frequencies (SA provides
1.5-2db more output than the best Cr02 in those ranges, equal
output at high frequency).
SA also outperforms the ferric-oxide tapes (regular and
cobalt-energized) which are unable to take full advantage of
the noise reduction benefits of the Cr02 equalization because
their high-end saturation characteristics are not compatible
with this standard.
Ask for TDK SA Cassettes.
Australian Distributor: Convoy International Pty. Ltd.
4 Dowling Street, Woolloomooloo 201 1 . 358 2088.
PF 648
Australia's first domestic
___ l
cable TV system
Although cable TV systems are very much a part of the domestic TV
scene in some overseas countries, notably Canada and US, such sys¬
tems have been unheard of in Australia — up until now that is. By
the time you read this, Australia's first domestic cable TV system should
be in operation in a housing commission complex in Melbourne.
Scheduled to commence operations
this September, Australia's first cable TV
system is a joint project of the Mel¬
bourne City Council and the Victorian
Housing Commission. It will serve about
4,000 tenants in the Debney's Park Hous¬
ing Commission Complex, and will
operate by cable from a studio set up at
the Debney's Park community centre.
Debney's Park is a complex in the
suburb of Flemington, on the fringe of
the city, and contains a number of high-
rise blocks. The closed circuit TV is seen
as a means of combating the loneliness
which sometimes afflicts people living in
high-rise communities.
Cabling from the community centre to
the Housing Commission flats was still in
progress as this article was written,
although some flats were to be con¬
nected for the opening in mid-
September. It is expected that 10-hours
of programs a week will be fed via the
existing coaxial cable master antenna
system.
The station will be run by the Debney's
Park recreational control panel, compris¬
ing seven representatives from the Deb¬
ney's Park community centre executive,
the local primary school, the Housing
Commission tenant's representative and
the City Council Parks, Gardens and
Recreation Department. Mr Gerry Quirk,
the City Council's recreation officer, will
be the station manager.
The system itself was designed by the
engineer's department of the City Coun¬
cil, and uses two AWA Rediffusion
closed-circuit TV carmeras — a studio
camera, with rear control zoom lens and
mounted on a tripod, and a hand-held
camera which can either be used with an
adaptor as a second studio camera or
with a portable video tape recorder. The
second camera also has a manual zoom
lens.
On the technical side, the production
director is able to view the outputs of the
two cameras on two monitors. The out¬
puts can be mixed through a video mixer
to provide fades, corner inserts, wipes
and other effects.
Output from the mixer is viewed on a
third monitor, and can either be ,
recorded on an electronic edit video
tape recorder or fed through a modula¬
tor to the Debney's Park Housing Com¬
mission flat complex. The mixer is
equipped with a function board which
enables synchronisation between the
portable video tape recorder and live
camera outputs, enabling effects to be
performed between these two inputs.
An AWA Rediffusion 12-inch monitor/
receiver is used to enable monitoring of
the output.
Two microphones are used for studio
sound recording, together with an audio
mixer. Two-way communication is
available between both cameramen and
the production director. The control
desk is portable, enabling it to be
transported to and from locations.
The aim is to train tenants in the use
of the equipment, so that eventually they
can run the station themselves. Programs
will revolve around activities at the
estate's community centre and will
mainly concentrate on entertainment
such as drama, singing and folk danc¬
ing.
The Debney's Park experiment may
well be the beginning in Australia of a
swing towards more community involve¬
ment in television and, in particular,
towards cable TV. In Britain, for example,
the use of cable systems has enabled at
least five large towns to set up non¬
commercial community networks which
may only concentrate on local people
and local issues.
Regulations in both Britain and Aus¬
tralia prevent the commercial use *of
cable TV, but many other countries have
no such restrictions. In Canada alone, it
is estimated about one-third of the
population receive TV programs via
cable.
Cable television, in more advanced
form, involves linking household
television receivers to a broadband
cable, which can carry far more channels
than available through the crowded air¬
waves, gives interference-free reception,
and can also be loaded with signals for
other communication services. How¬
ever, the future of cable TV is in limbo
in Australia at present, still dependent on
Government decision. $
— — I
I
Community operators use AWA Rediffusion camera equipment to record children's Reprinted from "The Australian Financial
activities. The aim is to provide 70 hours of programming per week. Review".
ELECTRONICS Australia, December, 1976 37
CS/RO research aids industry . . .
AC bridge circuit for
temperature measurements
A new, inexpensive AC bridge for use with platinum resistance ther¬
mometers for accurate temperature measurement has been developed
by the CSIRO National Measurement Laboratory, Sydney. The new
bridge makes possible temperature measurements to better than
.025°C over most of the range — 250°C to +550°C, with suitable
thermometers.
The platinum resistance thermometer
has been used for many years for the
most precise measurements of tempera¬
ture. The resistance of pure platinum
changes in a known and predictable way
with changes in temperature and is highly
reproducible. A platinum resistance ther¬
mometer usually consists of a resistor of
very pure platinum wire mounted in a
strain free condition and enclosed in a
suitable sheath for protection.
However, in the past the measurement
of resistance of such thermometers has
usually been made with expensive
precision DC bridges consisting of a mul¬
titude of precise resistors and high
quality switches. Drifts in value of these
resistors necessitates frequent and
expensive calibrations. The use of a
typical DC bridge is plagued by the
presence of thermal EMFs which can
make measurement difficult. AC tech¬
niques overcome the thermal EMF
problem but the other drawbacks
remain.
The new NML AC bridge uses a ratio
transformer in which inherently stable
and accurate ratios are maintained.
Precise resistance measurements nor¬
mally require some method of eliminat¬
ing the errors due to the resistance of the
leads connecting the resistor to the
bridge. The high input impedance of
typical ratio transformers permits simple
bridges to be made which are relatively
unaffected by reasonable values of the
lead resistances, but these systems suffer
from an extremely non-linear rela¬
tionship between the resistance
measured and the setting of the ratio
transformer. The combination of modern
integrated circuit operational amplifiers
with ratio transformers enables bridge
circuits to be constructed which over¬
come this problem.
The unit shown in the photograph is
made by Leeds & Northrup Australia Pty
Ltd, and is a commercial development of
a system developed at NML specifically
for platinum resistance thermometry
using mainly elements of 100 ohms
nominal resistance at the ice point. It has
a range of 0 to 300 ohms and an accuracy
of ±0.01 ohm.
The sensor current is 1mA at a
frequency of 80Hz, and the errors
introduced by a resistance of up to 10
ohms in any, or all, of the leads is neglig¬
ible. Small currents must be used to avoid
self heating of the thermometer.
The instrument comprises a sinusoidal
oscillator which excites an "active
bridge" network whose output is effec¬
tively zero in the balanced condition. The
bridge output is measured by a null
detector channel comprising a high gain
AC amplifier, phase sensitive detector
and DC amplifier stages..
The basic principle of the new bridge
network is shown in Fig 1 . The output of
#the oscillator, designated V, is applied to
* a controlled current source (CCS) and a
linear voltage divider, ratio k, which
represents the five measuring dials. The
controlled current source (CCS) has the
A commercial instrument based on the CSIRO's new bridge circuit has already been
developed . The unit shown above is made by Leeds and Northrup Aust. Pty. Ltd.
38
ELECTRONICS Australia, December, 1976
R TO NULL DETECTOR
— - ►
X (RESISTANCE IN
I THERMOMETER
BEING MEASURED)
FIG.1 BASIC OPERATING PRINCIPLE OF BRIDGE
property that its output current I is proportional to input volt¬
age (ie., I = (1/R).V where R is a transresistance) and is not
affected by the actual voltage appearing at its output terminal
due to a load impedance.
The current I flows through the unknown resistor X from
the output of an unity gain buffer amplifier connected to the
tapping point of the divider. Thus the voltage at the lower end
of X is kV, and the voltage at its other end becomes zero when
X = kR, which is the required balance condition.
The practical circuit, somewhat simplified, is shown in Fig
2. The CCS is formed by the integrated circuit operational
amplifier A1 and the two pairs of equal resistances R and Z.
The combination of positive and negative feedback gives the
constant current characteristic.
The unknown resistance X is shown as a four terminal con¬
nection with lead resistances r, which are not required to be
similar in value. Operational amplifier A2 is connected as a
"voltage follower" with the negative feedback taken from the
four terminal junction point Q. Thus the potential at Q is equal
to kV. The null detector A3 is connected to the other junction
P and the previous balance condition is unchanged by the
effects of the lead resistances.
CONSTANT VOLTAGE /
GENERATOR (80Hz)(~ J
INDUCTIVE DIVIDER
CONTROLLED
CURRENT
SOURCE
■4r I IWITV
UNITY GAIN
AMPLIFIER
FIG. 2 ARRANGEMENT OF COMPONENTS FORMING
BRIDGE NETWORK
The quadrature error signal which is always present with AC
bridges due to stray capacitance and inductance is relatively
small due to the low operating frequency, and is rejected by
the phase sensitive detector.
The accuracy of the bridge depends on the divider, which
uses the ratio transformer technique for the three most sig¬
nificant dials. These ratios, which depend on tapped trans¬
former windings, are inherently stable and unaffected by
ambient temperature or long term drift. Simple resistive net¬
works are adequately stable for the less significant dials.
The new bridge, which is available commercially for under
$800, should give research laboratories and industry the
capability of making accurate measurements inexpensively. It
has the additional advantage of being easily portable for in-
the-field measurements, and can operate either from batteries
or from an integral power supply. £
Welcome friends with their favorite t
as
, 0
Heathkit Electronic
“Doorbell” is one of
our most unique kits...
you program it to play your
favorite tune
What an exciting way for visitors to announce
themselves. ..your favorite melody plays
when they touch the door button. Use as
many as 16 notes to program your favorite
tune. Change it whenever you wish... pro¬
gram to celebrate a season, an anniversary,
a birthday, even a special party. And the TD-
1089 tells you whether a visitor is at the front
or rear door by the length of the tune.
Changing your tune is easy. Just rearrange
the programming leads in the connectors of
the C through C' “keyboard’’ located behind
the front-panel access door. The assembly
manual includes programming instructions
for a variety of tunes, or you can compose
your own. Controls for tuning, volume, speed,
and decay characteristics of the electroni¬
cally synthesized sound also are located in¬
side the front-panel door.
Single circuit board construction makes it
easy-to-build. And installation is easy too,
just wire between existing bell transformer
and TD-1089. The attractive brown plastic
cabinet with dull-gold color trim and tan fab¬
ric panels is included in the kit.
The TD-1089 is loud enough to be heard
throughout normal size homes, but you can
add extra 16-ohm speakers to the “exten¬
sion’’ terminals and spread the sound to
other areas.
The TD-1089
is easy to program.
Just remove
the decorative front
panel to change
programming
leads and make
adjustments.
; WARBURTON FRANKI HEATHKIT
■ CENTRE
■ 220 Park St., Sth Melbourne, 3205
• Ph. 699 4999
j Name . .
! Address
Postcode
ELECTRONICS Australia, December, 1976
39
Playmaster Forty/Forty
stereo amplifier
revised design has more power and even tower hum
We have had many requests for a higher powered version of the very
popular Playmaster Twin Twenty Five stereo amplifier, so here it is.
The new version offers more power and some other performance
aspects have been improved. Constructors can easily upgrade their exis¬
ting Twin Twenty Five to the new circuit, if they so desire.
by UREG SWAIN & LEO SIMPSON
Perhaps we should explain, at the out¬
set, that we were not keen to produce
a higher powered version of the Twin
Twenty Five. Why meddle with a design
which has proved to be very reliable and
popular? Several thousand have now
been built and there is no indication of
a decline in sales.
However, ever since Applied Tech¬
nology Pty Ltd of Hornsby, NSW, con¬
sulted with us regarding their own
higher-powered version, there has been
a constant stream of requests from rea¬
ders and kit suppliers to indicate what is
involved. If we were reluctant to do so,
it was simply because an increase in
power output from 25 watts to 40 watts
is a barely audible 2dB. To obtain a
worthwhile audible increase, the power
ratio really needs to be about 6dB, ie, 4
times the power.
Ultimately, some incentive to proceed
with the higher powered version was
provided by Dick Smith Electronics Pty
Ltd, They arranged for the supply of a
higher rated C-core power transformer
and thus overcame a number of practical
objections we had. The new transformer
fits into the existing chassis, so no altera¬
tions to the metalwork are required.
More importantly, the new transformer
has less external hum field.
In fact, the new transformer has less
external field than the smaller transfor¬
mer in the Twin Twenty five version. As
a result the amplifier is physically
quieter-the field is much less likely to
cause the metal lid of the case to hum.
Nor is there any sign of lamination buzz;
this can be frustrating in an amplifier
which is electrically very quiet.
A lower hum field also means that
there is less likelihood of hum being
induced into cassette decks or magnetic
cartridges— a very common problem in
hifi installations. We found that the new
transformer gives a 6dB reduction in
induced hum in typical magnetic car¬
tridges and cassette decks, compared
with the smaller transformer mentioned
above.
The C-core transformer is also more
efficient and runs cooler.
So the new transformer has enabled us
to improve the subjective performance
as well as upgrading the specifications,
adding up to a worthwhile all-round
improvement.
Other changes to the amplifier are less
noticeable. The class-A driver transistors,
T10, T110 and the constant current
source transistors, T9, T109 are now
higher rated BD139's and BD140's. The
thermal compensation transistors, T15
and Til 5, are now mounted on the rear
panel, adjacent to the power transistors.
Capacitors have been added to the
inputs of the power amplifiers to render
the output offset voltages independent
of the Balance control setting.
The new circuit and wiring diagrams
also incorporate a number of corrections
which have been noted since the original
articles were published. Readers con¬
structing Twin Twenty Five versions from
scratch may apply all the changes noted
above.
Previous articles in April, May, June
and September 1976 have disciissed the
amplifier circuit and performance in
detail, so we will only give a brief resume
of the circuit operation, beginning with
the power amplifier.
40
ELECTRONICS Australia, December, 1976
FOR
Designed by Leo Simpson. See E.A Dec. 1976
ATTENTION
This playmaster Forty Forty has
the low noise transformer. The
Twin 40 is a cheaper Amp with
a normal iron core transformer.
We do riot supply the Twin 40
and do not intend to.
FEATURES
"Simplified complete instruction
manual & assembly instructions
"Special silk screened fibre-
glass PC Board
"Level graduation on
Treble & Base
control
"Exclusive Bronzed An¬
odized front panel
PACKING &
POSTAGE FOR
PLAYMASTER
FORTY-FORTY
IS $5.00
"Professional knobs to
match front panel
OPTIONAL CABINET
Optional high quality
simulated Teak timber
cover, gives the Amplifie
that $500 look. Suits
both the Playmaster Twi
25 and the "Forty Forty
Cat. H-3113 .. .. $7.50
EXCLUSIVE C' CORE
LOW NOISE (LH) TRANSFORMER
The "C" core transformer in the Dick Smith kit is exclusive -
and its one of the key components in this amplifier. Normal
interleaved (laminated) transformers are alright — just — but
for optimum performance the "C" core, with its grain -?
oriented steel and better electrical characteristics is hard to
beat. The result: a quieter more powerful amplifier. More
power can be delivered by transformer with less "noise"
being radiated to get in the sensitive front end of the
amplifier.
ATTENTION: This amplifier is slightly more expensive
because of the "C" core (LH) low noise transformer —
however it is really worth the extra $5.00 — on head¬
phones alone the background noise level is noticeably
lower.
Cat. K-3411 Playmaster "Forty Forty" Kit $105.00
"C" Core Transformer only . Cat.^/To 148 $24.50
CONVERT YOUR TWIN 25
TO GIVE 40RMS PER CHNL
With this conversion kit — complete with full instructions —
you can now boost your Twin 25 to give 40 watts RMS per
channel. All necessary parts including "C" core transformer
etc.
Cat. K-3435 . Complete Conversion Kit only $25.00
FREE
POWER SUPPLY
_ CIRCUIT INCLUDED
If you purchase the conversion kit we include a full circuit
diagram to show how to use your existing Twin 25 Trans¬
former for a 13.8 volt 2-4 Amp Regulated supply — ideal
for bench use and CB Transceivers — a must for the hobbyist.
DICK SMITH ELECTRONICS GROUP
HEAD OFFICE: Phone 439 5311. Telex AA20036. Cable ‘Diksmit’ Sydney
MAIL ORDERS: P.O. Box 747, Crows Nest, N.S.W. 2065
N.S.W. BRANCHES: GORE HILL-162 Pacific hfwy, 439 5311
SYDNEY— 125 York St, 29 1126 BANKSTOWN— 361 Hume Hwy., 709 6600
INTERSTATE BRANCHES: QLD“~166 Logan Rd., Buranda 391 6233
VIC— 656 Bridge Rd., Richmond 42 1614
DICK SMITH DEALERS:
V Aero Electronics, Hobart (34 8232)
f* A Veneman & Wyatt, Darwin (81 3491)
1 Wills & Co., Launceston (31 5688)
. I Hunts Electronics, Toowoomba(32 6944)
MM A*E* Coo,in9. Elizabeth South(255 2249)
nb/ The Record Centre, Griffith (621 577)
~ Altronics Parts, 105 Stirling St,
Perth W.A. 6000 Ph 28 1599
Dealers prices may be higher due to transport costs!'
NOW YOU CAN BUILD THE FABULOUS
PLAYMASTER "FORTY FORTY
42
ELECTRONICS Australia, December, 1976
T6 and T7 form a differential pair which
enables the amplifier quiescent output
voltage to be set close to OV and thus
eliminate output capacitors. Current
through the differential pair is set by the
constant current source T8 which uses
D1 and D2 as its voltage reference. To
ensure that the differential input stage
remains balanced even at very high
frequencies, T7 has a collector resistor of
the same value as T6, ie, 680 ohms. This
ensures that the voltage excursions at the
collectors of T6 and T7 are always
similar.
Constant current source T8 provides a
high degree of hum rejection and also
enables the differential input stage to
maintain control over the output offset
voltage, even when the balanced supply
rails fall to a value of only a few volts (as
happens after switch-off). The net result
of this is that there is no delayed thump
from the loudspeakers after switch-off.
Signal output from the differential
input stage is taken from the collector of
T6 and amplified by common emitter
stage T10. Local feedback in this stage is
in the form of emitter degeneration
provided by the 39 ohm emitter resistor.
No-signal current through T10 is set by
constant current source T9 which also
uses as its voltage reference, D1 and
D2.
T10 would normally provide a very
high source impedance for the following
stages by dint of its constant current
source load T9. This is undesirable for
several reasons, so both sides of T15 are
tied to the 0V line with 4.7k resistors.
This makes the collector load of T10
about 2.3k and renders the voltage gain
of this stage almost independent of the
output stage loading.
A more important advantage of this
arrangement is that it provides voltage
drive to the output stages and thus ena¬
bles them to achieve a much better
bandwidth.
The output stages operate essentially
as Darlington emitter followers with no
voltage gain but considerable current
gain.
Til and T13 combine to form a con¬
ventional Darlington emitter follower,
while T12 and T14 form a compound
transistor also operating as an emitter
follower. Diode D3 provides the same
overall Vbe drop as the T11/T13 Darling¬
ton and thus helps to make the output
stage more symmetrical. The .022uF
capacitor across D3 compensates for the
load capacitance in the collector circuit
of T12 due to the Miller capacitance of
the base-collector junction of T14. The
capacitor thus gives another small
improvement in output stage symmetry.
Voltage gain in the amplifier is set by
the ratio of the 22k and Ik resistors in the
base circuit of T7. Low frequency
response is set by the 22uF feedback
capacitor.
An RLC network at the output of each
power amplifier ensures unconditional
stability. This RLC circuit was developed
by A. N. Thiele and published in Proc.
IREE September 1975. As a bonus, the
network prevents RF interference picked
up by long loudspeaker leads being fed
back to the amplifier input via the feed-,
back network.
The phono preamplifier is similar to
that featured in the November 1973 issue
of "Electronics Australia". T1 and T2 form
a differential amplifier with balanced out¬
put to drive the 741 operational amplifier.
The sole purpose of using the transistors
is to improve the otherwise inadequate
noise performance of the 741.
Collector current of the two input tran¬
sistors is set at about 87uA by the com¬
mon 82k emitter load resistor. As another
measure to minimise noise output, the
collectors of T1 and T2 run at the quite
low voltage of about 2.4V.
Five components are used in the
equalisation network (560k, 56k, .0056uF,
.001 2uF and 150pF) to give an RIAA
response within IdB.
Low frequency response of the
preamplifier is rolled off below 30Hz to
minimise rumble reproduction. The roll¬
off is determined by the ratio of the reac¬
tance of the IOuF capacitor to the Ik
resistor in the feedback network.
A 47pF capacitor and Ik resistor are
used at the phono inputs as an RF
attenuation network. This network
causes a slight degradation to the signal/-
noise ratio of the preamplifier but is a
necessary measure (along with others in
the circuit) to ensure that the amplifier
is not prone to RF breakthrough.
The series network consisting of the 1 k
resistor and .001 uF capacitor between
PERFORMANCE OF PROTOTYPE
POWER OUTPUT One channel
4 ohms 54W
8 ohms 40W
1 6 ohms 24W
Both channels
43W
34W
2 1 W
FREQUENCY RESPONSE
Phono inputs
High level inputs
RIAA equalisation within IdB
from 30Hz to 20kHz
25Hz to 20kHz ± IdB
CHANNEL SEPARATION
(with respect to 40W)
10kHz
1kHz
100kHz
— 33dB
— 46dB
— 48dB
INPUT SENSITIVITY
Phono at 1 kHz
Overload at 1 kHz
High level inputs
2.8mV
1 20mV
1 80mV
56k
36k (minimum)
HUM & NOISE
Phono (with respect 1 0mV)
Other inputs
70dB unweighted with
typical cartridge
70dB unweighted with
inputs open circuit
TOTAL HARMONIC DISTORTION
At full power with both channels operating
from 25 to 20kHz: less than 0.3%
Typically less than 0.1 % at normal listening levels
TONE CONTROLS
Bass
Treble
+ 12, — 1 3dB at 50Hz
± 10dB at 10kHz
DAMPING FACTOR
at 1kHz
at 30Hz
> 60
> 30
STABILITY
Unconditional
1
ELECTRONICS Australia, December, 1976
43
Your
next electronic circuit
tester should be a
San wo
N— 501
•2jUA suspension movement
— 0.05mA/1 mV resolution
• Double protection — fuse
& Si diode
•Constant IMft input
impedance (ACV) —
RF-diode rectified current
direct to movement
• Revised scale marking — •
intermediate readings
readily determined
• Multifarious application —
as circuit analyser
±DC V 0-60mV 0-0.3-1 .2.3-
12-30V (500kft/V)
0-1 20-300-1 ,2 k
(50kft/V) ±2%
0-30k (w/HV probe)
±DCA 0-2) US 0-0.03-0.3-1 .2
-3-1 2-30mA
0-0.12-0.3-1.2-12
(300mV) ±2%
ACV 0-3r1 2-30-1 20-300-
1.2k ( 1 Mft)
±2.5% Freq. 20Hz
dB
to 50kHz (±1dB)
0-1 .2-1 2 A
xl xIO xlOO xl k
xlOk xIOOk (max.
200M)
Batt. 1.5Vx1 &
9Vx1
-20 to +63
252x191x107mm 1.95kg
L
460— ED
• 10jLtA movement —
lOOkft/V, varistor
protected
• Polarity reversal switch —
negative measurements
• Equalizing transformer —
common shunts & jacks for
1.2 A & 12A DC/AC
• Detachable indicator block
— easy maintenance
• Accurate DC reading — no
HF current interference
±DCV
0-0.3-3-12-30-120-
300 OOOkft)
1.2k (16.6kft/V)
±2% 30k
(w/HV probe)
±DCA
0-12jUA 0-0.3-3-30-
300mA 0-1.2-12A
(300mV) ±2%
ACV
0-3-12-30-120-300-
1.2k (5kft/V)
±3% Freq. 20Hz to
1MHz at 3V
ACA
0-1.2-12 (300mV)
±3%
ft
xl xIO xlOO xlOk
(max. 50M)
Batt. 1.5Vx1 &
9Vx1
dB
-20 to +63
184x134 x88mm 1.3kg
U-60D
• Measurement ranges
available.
DCV 0.1 0.5 2.5 10 50
250 1000
(20kft/V) (25kV
w/HV probe extra)
ACV 2.5 10 50 250
1000 (8k 12/ V)
DCmA 0.05 2.5 50 500
(500mV drop;
lOOmV for
0.05mA)
ft Range -XI X10
X100 XI k
Midscale — 50ft
500ft 5kft 50kft
Maximum — 5kft
50kft 500kft 5Mft
Batteries 1 ,5V dry
cell
(UM-3 or
equivalent)
X2
LI 0.06mA 0.6mA
LV 3V 3V
LI 6mA 60mA
LV 3V 3V
• Allowance.
Within ±3% f.s.d. for DCV
& DCmA
Within ±4% f.s.d. (±6% for
2.5V) for ACV
Within ±3% of scale length
for ft
•Size & weight.
133X92X42 mm & 300 gr
7Shf
75 years of service
to Australian industry.
P-2B
• The sturdy midget — quality
quality instrument of
functional design
• Designed for rugged service
— phenol-resin front panel
& metal rear case
•Positive range setting —
special feature of a pinjack
tester
• Reserve instrument — for
household or field service
DCV 0-1 0-50-250-500-1 k
(2k ft/V) ±3%
DC A 0-0.5-10-250m
(670mV) ±3%
ACV 0-1 0-50-250-500-1 k
(2kft/V) ±4%
ft 0-5k 500k
Battr 1 .5Vx1
dB -20 to +36
Mft 0.1—50 ) using
jUF 0.0002—0.6 ) external
power
1 20x88x40 mm 325gr
ADELAIDE 356-7333 • BRISBANE'52-7255 • HOBART 23-1841
MELBOURNE 699-4999 • PERTH 65-7000 • SYDNEY 648-171 1
• WELLINGTON N.Z. 698-272
44
ELECTRONICS Australia, December, 1976
TRANSFORMER
PLAYMASTER FORTY/FORTY
RMS, which means that it has more than
adequate input overload margin.
Signals from the volume control are
fed to an emitter-follower stage T3
before passing to the active tone control.
T3 provides the required low source
impedance for the tone control stage and
minimises the loading on the volume
control so that it provides smooth
progressive action.
The active tone control is basically a
negative feedback circuit around stages
T4 and T5. T4 is a common emitter
amplifier with bootstrapped collector
load. T5 is an emitter follower which is
an output buffer.
Power supply circuitry is simple. A
centre-tapped bridge rectifier circuit
produces the positive and negative 35V
rails for the power amplifiers. From these
rails are derived the positive and negative
15V rails for the small-signal stages. Two
15V zeqer diodes are used here and they
are bypassed with large value electrolytic
capacitors to reduce "zener" noise and
provide a further degree of hum filtering.
The pilot light is a LED run from the nega¬
tive 35V rail via a 2.2k resistor.
This completes the description of the
circuit apart from the optional
loudspeaker protector which wa$ fea¬
tured in June 1976 (File 1/SA/57). Now
a brief discussion on the performance of
the new amplifier.
Notice that the title "Forty /Forty" is
only an approximate guide to the power
output. The maximum power figures we
give are for continuous sine wave output
at 1kHz, at just before the onset of clip¬
ping with a mains voltage of 240VAC.
Altering any of these parameters slightly,
i.e., load impedance, mains voltage or
degree of clipping (say to 1% THD) can
alter the figures quite markedly.
All specifications refer to the whole
amplifier from input to output, not just
the power amplifiers. The distortion
ratings apply to all inputs, including the
phono input.
During normal operation the amplifier
output transistors will be cool or just fain¬
tly warm to the touch. However, if con¬
tinuous sine wave testing is performed
which produces maximum dissipation in
the output transistors they will become
extremely hot— up to 120 degrees Cel¬
sius. This is hot enough to burn fingers!
Even at this high temperature the transis¬
tors will be within their ratings.
It is normal for T9, T109, T10 and T110
to become fairly hot to the touch, even
when the amplifier is idling. On the other
hand, the driver transistors Til, Till, T12
and T112 should normally be cool to the
touch.
Some readers may query the operating
conditions of the output transistors. It is
true that if the balanced supply rails
exceed ±35V then the 2N3055 Veer
rating can be exceeded. However,
experience with amplifiers of similar
design has shown that a breakdown due
to this cause is most unlikely. Similarly,
the voltage rating of the 4700uF/35VW
PARTS LIST
CHASSIS & HARDWARE
7 plated steel chassis 370 x 80 x 245mm
(W x H x D) with cover
7 front panel
5 knobs to suit front panel
2 miniature SPST toggle switches
7 miniature DPDT toggle switch
7 6.5m stereo jack socket with switch
contacts (plus insulating washers)
1 LED for pilot light
2 6-way RCA socket panels , Ralmar
M421 or equivalent
7 4-way spring loaded terminal panel ,
Ralmar ST3 or equivalent
7 rotary 2-pole , 4 position switch
7 100k (lin) dual ganged potentiometer
7 50k (log) dual ganged potentiometer
7 50k (lin) potentiometer
7 25k (lin) dual ganged potentiometer
6 Richco CBS-6JV PC board supports
4 rubber feet
6 solder lugs
7 mains cord clamp and grommet
7 3-way insulated terminal block
7 three-pin mains plug and three-core
mains cord
7 metre of 10-conductor rainbow cable
2 metres of figure-8 shielded cable
4 sets of mounting hardware for TO-3
power transistors , /e, mica and insula¬
ting washers plus screws and nuts
2 .047uF/25VW ceramic or metallised
polyester capacitors
1 .01uF/2kV ceramic capacitor
2 4-lug tagstrips
1 transformer DSF M-0148 52V CT
MAIN PC BOARD
7 PC board , 76sa4
8 fuse clips , Swan (McMurdo) FC1 Part
No. 1397-01-18
4 2 amp 3 AG fuses
2 14uH chokes , Paradio VPC 14A or
equivalent
2 1k preset potentiometers
SEMICONDUCTORS
4 1N5408 or 100PIV 2 amp silicon
diodes
2 BZX79/C15 zener diodes
6 1N4148, 1N914A silicon signal diodes
4 2N3055 silicon power transistors
4 BD139 NPN silicon transistors
4 BD140 PNP silicon transistors
46 ELECTRONICS Australia, December 1976
filter capacitors will be exceeded when
the mains voltage exceeds 240VAC.
However, the capacitors will still be
within their surge voltage ratings so
breakdowns are again unlikely.
Assembly can begin with the PC board.
Proceed carefully and double check ^ll
components as many mistakes can be
made here. Refer to the circuit diagram
and PC board layout diagram as assem¬
bly progresses. No particular order of
component installation need be
followed other than to insert the long
links of hook-up wire before adjacent
components. ,
Transistor designation on the board is
the same as on the circuit, i.e., T1, T2 etc.,
while the duplicate channel is T101, T102,
etc.
PC stakes are recommended and any
type may be used provided they are a
tight fit in the PC board holes before sol¬
dering. If PC stakes are used they have
the advantage that all connections to the
board can be quickly broken to allow the
board to be completely removed from
the chassis.
Low noise cracked carbon or metal
film resistors of ViW or Vi\N rating may
be used throughout except where we
have noted otherwise, on the circuit
diagram. Insert all the resistors so that
their colour code bands run in the same
direction. This makes component check¬
ing easier.
Ensure that tantalum and aluminium
electrolytic capacitors are correctly
inserted, otherwise they will be reverse
polarised and rendered ineffective. Tan¬
talum capacitors are coded with a dot (as
shown on the PC layout diagram) or plus
sign to indicate polarity.
8 BC547, BC107, BC182 NPN silicon
transistors
10 BC549, BC184 NPN low-noise transis¬
tors
2 uA741 operational amplifier integra¬
ted circuits
CAPACITORS
2 4700uF/35VW pigtail electrolytics
1 1000uF/16VW PC electrolytic
1 470uF/16VW PC electrolytic
2 22uF/6VW tantalum electrolytics
4 10uF/25VW tantalum electrolytics
6 4.7uF/25VW tantalum electrolytics
2 1uF/25VW tantalum electrolytics
6 0.47uF/25VW tantalum electrolytics
17 0.1 uF/60VW metallised polyester
(greencap) or ceramic capacitors
2 .047 metallised polyester
2 .022 metallised polyester
4 .0068uF metallised polyester or
polystyrene
2 .0056uF metallised polyester or
polystyrene
2 .0033 metallised polyester or poly¬
styrene
2 .0022 metallised polyester or poly¬
styrene
Quite a diverse range of transistors
may be used on the board apart from
those in the output stages. TO-92 tran¬
sistors are preferable to those in metal
encapsulation both from the cost angle
and the fact that transistors with col¬
lectors connected to the metal can are
more prone to parasitic oscillation. If you
are supplied with substitute transistors
not listed in our parts list make sure of
the following:
(a) obtain the dealer's assurance that the
substitutes are in fact equivalent and
(b) obtain from him a diagram of the lead
* connections.
As a precaution against instability we
recommend fitting a ferrite bead, type
FX1115, to the base leads of T3 (and
T103). Sleeve the base lead before. fitting
the bead. This is to prevent noise caused
by the bead's finite resistance altering the
bias conditions of the transistor. It is not
necessary to sleeve the emitter and
collector leads.
Take great care in inserting transistors.
Notice that the BD139 and BD140 driver
transistors are differently oriented— the
metal flat on the BD140s faces to the rear
of the chassis while on the BD139s it
faces to the front. Notice also that T9
(T109) and T10 (T110) are differently
oriented. The metal flat on T10 (BD140)
faces to the rear of the chassis, while for
T9 (BD139) the metal flat is on the side
facing away from the power trans¬
former.
While we have designed the copper
pattern around 14-pin ICs for the 741s,
the PC board is also compatible with
both the 8-lead "mini-dip" and 8-lead
metal can versions of the 741. This is by
virtue of the fact that pins 1, 2, 7, 8, 12,
13 and 14 have no internal connection
(on the 14-lead 1C), while the remaining
pins have the same orientation as in the
smaller packages.
For both 8-lead packages, pins 1 to 4
connect to pins 3 to 6 of the socket pat¬
tern and similarly, pins 5 to 8 should con¬
nect to pins 9 to 12 of the socket pattern.
The PC board layout diagram shows
mini-dip ICs in position.
We used 1N5408 rectifier diodes as
supplied by Dick Smith Electronics.
These have the advantage of economy,
but if they cannot be obtained any power
diodes with a rating of at least 2 amps
at 100PIV will suffice.
Notice that diodes D3 and D103 point
in opposite directions on the PC layout
diagram.
8 Swann (McMurdo) FC1 fuseclips are
used on the PC board. These are inserted
and the solder tags crimped on the cop¬
per side before soldering to ensure that
they are mechanically secure. But do not
insert the four fuses until after the
setting-up procedure has been success¬
fully completed.
Six 1 ohm/1 W resistors are used in
each power amplifier output stage.
These are used instead of equivalent
resistors of higher rating, because they
are cheaper and often more freely avail¬
able. However, if the 1 ohm/1 W resistors
cannot be obtained, two 0.33 ohm/5W
resistors can be used for each power
amplifier.
The 14uH chokes are wound with
eighteen turns of 20 B&S enamelled cop¬
per wire on a special grade of ferrite rod
•30mm long and 10mm diameter.
Ordinary ferrite rod used for AM radio
antennas is not suitable. We understand
that at least one kit retailer will be supply¬
ing ferrite rods of correct grade plus wire.
Alternatively, Paradio Electronics, 7a Bur¬
ton Street, Darlinghurst, NSW, can sup¬
ply trade requirements for finished
chokes which have type number
VPC14A.
A length of shielded cable is required
to connect both of the amplifier inputs
to the balance control terminals. This is
to tie the power amplifier input earth
points to the rest of the board earth net¬
work. Leave the inner conductors of the
shielded cable disconnected from the
amplifier inputs for the time being.
This completes assembly of the PC
board. Next month we will describe the
installation of hardware in the chassis,
and detail the setting-up procedure. A
useful trouble-shooting procedure will
also be included for those who run into
difficulties.
2 .001 2uF metallised polyester or poly¬
styrene
2 .001 metallised polyester or poly¬
styrene
2 150pF ceramic or polystyrene
2 47pF ceramic or polystyrene
2 33pF ceramic or polystyrene
RESISTORS
(5% tolerance , 14 W, unless otherwise
noted)
2 x 1 M, 2 x 820k , 2 x 560k, 2 x 270k , 4
x 220k, 2 x 82k, 8 x 56k, 5 x 22k, 2 x 15k,
10 x 10k, 10 x 4.7k, 6 x 2.7k, 5 x 2.2k,
2 x 1.8k, 1 x 1.5k, 12 x1k,4 x 680 ohms,
2 x 470 ohms/1 W,2x 330 ohms, 4 x 270
ohms, 2 x 220 ohms, 2 x 180 ohms, 2
x 150 ohms, 6x6 8 ohms, 4 x 39 ohms,
2x10 ohms/YiW, 12 x 1 ohm/IW , 4 x
100 ohms/1 W (see text).
NOTE: Resistor wattage ratings and
capacitor voltage ratings are those used
for out prototype. Where voltage
ratings are not quoted, they should be
50V or more. Components with higher
ratings may also be used provided they
are physically compatible.
The 1976/77
YEARBOOK
is on sale at your newsagent now.
Don't miss our article on CB radio.
Price $1.20
Pry Ltd.
THEY’RE EVERY
MICROPHONE
YOU EVER
CardiciD ^ WANTED.
Omnidirectional
Head
Powering
Module
Mini-Shotgun
Head.
SEIMNHEISER
We have taken the latest advances in
electret technology one step further. By
combining them with advanced acoustic
technology to make professional condenser
microphones more portable.
One common powering module (K2U)
serves three different compact heads:
omnidirectional (ME20), cardioid (ME40)
and mini-shotgun (ME80). Thus, for
most studio and location situations, it’s
no longer necessary to carry three
different microphones. Each head
contains its own microphone capsule
and “front-end” electronics, all exactly
matched to its own precisely-controlled
acoustical environment.
The Powering Module runs on a single
5.6V battery, or phantom-powered
directly from your recorder, preamp or
other auxiliary equipment. Best of all,
of course, is the great versatility. In a
matter of seconds, you screw on
whichever head you need and go!
Powering module and heads are
available separately.
Australian Agent
fttf'Cutminyfiom
VIC.: 493-499 Victoria St . West
Melbourne. 3003 Ph 329 9633
N.S.W.: 4-8 Waters Rd . Neutral
Bay. 2089 Ph 909 2388
W.A.: 256 Stirling St . Perth.
6000 Ph 28 3655
QLD.: L. E BOUGHEN & CO .
Cnr Milton & Baroona Rds..
Milton 4064 Ph 36 1277
S.A.: Werner Electronic
Industries Pty. Ltd., Unit 25.
28 Gray St.. Kilkenny. 5009
Ph.: 268 2801
Telex Melbourne. 31447
Sydney. 21707 Brisbane.
41500 Perth 93244
RHC 6566
ELECTRONICS Australia. December. 1976
47
Simple to make— intriguing to use:
A telephone amplifier
Here's a little gadget that will allow you to listen to both sides of a
normal telephone conversation. While a rather primitive device in some
ways, it does provide the basis for a good practical lesson and it may
also open the way to the construction of something a little more
ambitious.
by WALTER NEVILLE
The idea behind the gadget is simple
enough: we have all had the experience
of having to listen to one side of a phone
conversation in which we were vitally
interested; say with an old friend or a sick
relative. After it's all over, the person who
took the call has to try to remember what
the other person said.
And there's another situation, all too
familiar in the office: we call someone
who is busy and are asked to wait on,
which usually means sitting in enforced
idleness, with one hand holding the
phone. With a suitable listening aid, it
may be possible to lay the handset down
until a voice says: "Putting you through
now. Sir".
Or that most frustrating question:
"Were you waiting on somebody?"
So, if a signal is to be picked up from
the phone for amplification, it has to be
picked up inductively — that is, by a suita¬
ble iron-cored coil, taped to the handset
or to the body of the instrument, where
it will sense the tiny stray magnetic fields
radiated by the telephone's own induc¬
tors.
A decade ago, it was a fairly simple
operation, because the inductors in the
then-current instruments had quite a
strong stray field, relatively easy to inter¬
cept. With the more modern handsets,
the stray field is much weaker, calling for
a more efficient pick-up coil, more cri¬
tical placement on the phone and more
amplification.
Unfortunately, a pickup system with
increased sensitivity is likely also to be
Our version of the
amplifier.At centre
top is transistor Q7
with Q2 to the right
of it. Q3 and Q4 are
towards the front
between the two
transformers. Note
the enlarged holes
in front of the
speaker.
Superficially, it would seem to be quite
easy to dream up a gadget to overcome
such problems: Simply make a connec¬
tion to the phone line and feed the signal
into an amplifier and loudspeaker, so that
everything on the line is amplified to
comfortable listening level.
Unfortunately, it isn't quite as easy as
that, because telephone authorities have
some very rigid rules about what can be
connected to their lines, and who by! In
any case, a suitable isolating transformer
would have to be used, otherwise direct
connection of an amplifier, particularly
one linked to mains or earth, could cause
complications.
more sensitive to stray fields from the
50Hz power wiring. Thus, if the signal in
the phone is on the weak side, the pickup
coil and amplifier will produce mainly
50Hz buzz, with very little voice. So the
amplifier circuit has to be tailored to
discriminate as much as possible against
"hum" frequencies, while still leaving
enough of the voice frequencies to
preserve intelligibility.
One other point has to be watched: If
the sensitivity of the loudspeaking sys¬
tem is too high, it may produce obvious
acoustic feedback into the telephone
microphone; the whole system will howl,
unless the gain is turned down, or the
handset is moved further away from the
loudspeaker.
If one sets out, therefore, to produce
a serious telephone amplifier, it tends to
develop into a fairly complex piece of
equipment, taking account of both elec¬
trical and functional requirements. It
might typically be mains operated to
save batteries; it might be built into a
decorative phone stand to avoid having
an awkward thing like an amplifier on the
table or shelf; it would have convenient
controls so that it could be adjusted or
turned down as necessary; it might have
a second cradle for the handset, while
awaiting a call, and so on.
By the time one gets through such an
exercise, there is a tendency to question
whether it is warranted so that, in prac¬
tice, telephone amplifiers rarely emerge
either as a do-it-yourself project or as a
commercial product.
That is, until one looks through the
Tandy Electronics catalogue and comes
across their Science Fair "learn while you
build" kit 28-116. Retailing at $11.95, it
makes no attempt at being decorative or
functional but it has one important fea¬
ture in its favour: it exists and it therefore
provides the interested reader with a
starting point!
At the time of writing, Tandy advise
that their stocks of this kit are rather
limited, so first in— first served. But if you
miss out, there is no reason why the cir¬
cuit cannot be built from standard bits
and pieces available from most elec¬
tronics suppliers. More about this later,
We imagine that some readers will
build it up, learn by so doing, play with
it for a while, and then strip it down to
recover the components for the spare
parts box. They may even use the pickup
coil to feed telephone signals to a tape
recorder via the mic. socket. Others may
be inspired to rebuild the gadget into a
decorative and functional case deserving
of a more permanent place in the home
or office.
This is up to you.
As with most others of these little
Science Fair kits, the instructions suggest
building the telephone amplifier on the
red plastic box in which the parts are
packaged. The box is coded with letters
and numbers which form the basis for the
step-by-step construction leaflet. If the
uninitiated constructor reads through the
leaflet, follows each step and checks it
off, a complete and working telephone
amplifier should result.
Rather than clip the component leads
48
ELECTRONICS Australia, December, 1976
short, we would favour keeping them to
normal length, merely bending them
aside and soldering as necessary. If you
do want to recover the parts, or decide
later to assemble them in another
physical form, they can be unsoldered
and the leads straightened, ready for
re-use. In fact, the layout of a little
amplifier like this is not at all critical and
it can be built up in almost any form you
like, provided the proper electrical con¬
nections are made.
And, speaking of electrical connec¬
tions, make sure that you carefully iden¬
tify the emitter, base and collector
connections on the transistors from the
literature in the kit, before actually install¬
ing them. The way the leads go in the pic¬
torial diagram isn't quite as clear as the
drawing might suggest and it is very easy
to get them mixed up.
The other small point we noticed is
that one of the transformers is supposed
to be "painted red", to distinguish it from
its companion unit. In the sample kit, the
top of the transformer had indeed been
hit with a red mist from a spray gun, but
so fine that we completely overlooked
the few tiny red droplets the first time
around!
Otherwise, everything went together
as intended.
We did make one deliberate modifica¬
tion, which will be evident from the pho¬
tograph. The instructions suggest that the
loudspeaker be mounted inside the red
plastic box, so that it radiates only
through the tiny holes already provided
in the box. Guessing that the unit would
not have any power or sensitivity to
spare, we drilled the holes in front of the
speaker to 3/1 6in — before the speaker
was mounted of course!
The circuit used in the 28-116 kit is
conventional, and the sort of thing that
was almost universal as the audio
amplifier in the first generation of transis¬
torised portable radios.
The input signal — in this case from the
telephone input coil — is fed to a 5k
volume control, and thence via a capaci¬
tor to the base of an ordinary general
purpose PNP germanium transistor. Its
emitter is connected directly to the
"earthed" positive supply rail, while two
series resistors from collector to emitter
provide the requisite forward bias for the
base. The collector itself is supplied from
the — 9V line through a 22k resistor,
across which the amplified signal
appears.
The collector of the first transistor is
coupled directly to the base of the
second, so that it shares the same signal
and the same DC potential. It is bypassed
to the earthy line by a 0.1 uF capacitor
which drastically reduces the response of
the circuit to the higher audio frequen¬
cies, minimising the unnecessary noise
and distortion components from the
input signal, without detracting from
voice frequencies.
Since the base of the second transistor
operates at a significant negative poten¬
tial, it is necessary to allow the emitter
also to move towards the negative
potential so that the transistor will have
only a modest effective forward bias.
This is accomplished by providing a fairly
large value of emitter resistor, bypassed
by a capacitor to obviate any loss of gain
due to emitter feedback. The collector of
the transistor runs to the — 9V supply
through the primary winding of a small
interstage transformer.
in opposite directions, they tend to can¬
cel in their magnetising effect on the
transformer core.
When out-of-phase signals are applied
to the bases of the respective output tran¬
sistors, the collector currents no longer
balance. Thus, at a particular instant, the
base of the upper transistor may receive
a negative-going half cycle of signal,
which will increase its collector current;
at the same instant, the lower transistor
The circuit of the phone
amplifier is conventional ,
even if somewhat dated.
The main points to watch
during assembly are the
correct identification of
the transistor leads and
the polarity of the elec¬
trolytic capacitors. A
largei . more efficient
speaker will improve
results considerably.
4.2SBS4 AC122 AC125 AC12#
As the collector current through the
primary winding of the transformer
varies with the signal, it induces signal
voltage in the secondary winding, the sig¬
nals at the two outer ends being of equal
amplitude but opposite phase. The sig¬
nals are fed to the respective bases of the
two output transistors operating in what
is known as push-pull class-B.
In broad concept, the "push-pull" part
of the term signifies that the two output
transistors complement one another in
supplying drive to the output transformer
and thence to the loudspeaker.
If no signal is present, a similar order
of current flows from the centre-tap of
the output transformer to the respective
collectors; since the currents are flowing
will receive a positive-going signal,
thereby decreasing its collector current.
On the next half-cycle of input signal,
the reverse happens.
Thus the two transistors tend to
complement one another in varying the
normally balanced currents through the
output transformer primary, and there¬
fore in modifying the magnetic field in
the transformer core. And, as the mag¬
netic field changes, current is induced in
the secondary winding and passed to the
loudspeaker voice coil.
The "class-B" part of the definition
implies that the transistors have only a
small amount of forward bias — applied
through a 15k and a 270 ohm resistor-
so that they draw only a very small cur-
Try this hum-bucking trick
As mentioned in the body of this
article, a problem with inductive
pickup is that of 50Hz pickup from the
mains. Just how serious this is
depends on several factors; the loca¬
tion, the "tailoring" of the amplifier's
low frequency response, and the
strength of the incoming signal.
This latter factor can vary over a very
wide range. The strongest signal will
probably ride over most hum
problems, but the weakest ones, which
may still be adequate as a telephone
signal, can easily be drowned by
typical hum levels.
We considered various possible
solutions. One was to provide a
"notch" circuit tuned to 50Hz; some¬
thing which can be provided relatively
easily these days, using low cost ICs.
(p 8 1 , Electronics Australia, November
1976.)
Such an arrangement would un¬
doubtedly provide considerable
benefit, but it does have one limitation.
It can only reject the fundamental
50Hz signal; it can do nothing about
the harmonics (100Hz, 1 50Hz, etc)
which, in many cases, are quite
strong.
Then we had another idea. Could the
hum be cancelled by picking up an
equal but opposite signal containing
hum only? To cut a long story short we
borrowed another pickup coil from our
friendly neighbourhood supplier, con¬
nected the two together appropri¬
ately — and it worked. Using a "worst
case" set-up, the hum dropped from
a nasty background to virtual
inaudibility.
To provide the required phasing we
connected the two outer shields to¬
gether and took the signal from the two
active leads. The two pickup coils were
place side by side in the handle slot in
the back of the phone, one in the best
place to pick up signal, and the other
as far from it as possible.
In theory this arrangement leaves
the wiring unshielded against electros¬
tatic pickup. In practice, at the rela¬
tively low impedance involved, hum
from this source was negligible.
ELECTRONICS Australia, December, 1976
49
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TRUE HI FIDELITY THAT
EVERYONE CAN AFFORD!
589
Our normal Complete system
separate item price
• Realistic STA-90 AM/FM stereo receiver.
• Two Realistic Nova 6 walnut veneer
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(3") tweeter.
• Realistic BD-1000 manual heft drive turntable.
THERE’S A TANDY
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50
ELECTRONICS Australia, December, 1976
rent under quiescent (or no-signal) con¬
ditions. This being so, most of the change
in the magnetic status of the core is
brought about as the output transistors
in turn draw more current on successive
half-cycles of the input signal; in this
case, where they receive a negative¬
going signal pulse.
While much could be said about
class-B operation, it has two particular
attractions in simple, inexpensive
amplifiers: it minimises drain on the bat¬
tery and it also minimises dissipation in
the output transistors.
In fact, the kit supplies simple general
purpose PNP germanium transistors for
all positions. The only concession is in
the provision of "flag" heat sinks for the
two used in the output stage - just in
case they are called on to handle a con¬
tinuous loud signal, sufficient to cause
some temperature rise.
Because this general type of amplifier
was almost universal in the first genera¬
tion of small transistor sets, it may in fact
be possible to adapt the audio end of a
discarded transistor receiver as a
telephone amplifier, feeding a pickup
coil into the volume control circuit in lieu
of the original radio signal for the detec¬
tor. Similar amplifiers have also been
used in small intercom systems and it
would be worth looking for a discarded
one of these.
So much for the circuit. How does it
all work out in practice?
Instructions in the kit suggest that the
pickup coil, with its suction cup, be
attached to the rear of the handset just
behind the earpiece. This may be okay
with some handsets (presumably
American) but with local handsets more
pickup was evideht with the coil right at
the end adjacent to the earphone.
Picking up the signal near the
earphone has an important advantage in
that the amount of energy from the local
microphone and the distant voice is fairly
well balanced. Unfortunately, however,
the signal is quite limited and may not
be enough with many handsets to drive
the amplifier when the distant voice is
weak.
A much larger signal is available, with
local handsets, from inside the handle
slot at the rear of the instrument. Lift the
receiver so that the dialling tone is heard,
and you will soon be able to select the
point of strongest pickup. Here, dialling
tone, selector clicks and local voice will
all be very loud relative to the distant
voice but there may be no real choice
if the amplifier is to be adequately
driven.
At best, however, one of the limiting
factors in the 28-116 kit is the tiny speaker
and the fact that the listening has to be
done right near the phone. The leaflet
suggests that a clearer signal will be
obtained if the amplifier is used with a
larger, more sensitive 8-ohm speaker—
particularly if you place it where you can
listen conveniently. Then you should be
able to hear both sides of the conversa¬
tion with less distraction.
Another possibility, which is well
worth considering, is that of using the
amplifier with a miniature earplug, con¬
nected in lieu of the speaker. Ordinary
8-ohm magnetic units appear to work
very well.
Earlier we suggested that components
should be available from sources other
than the Tandy kit. Those worthy of
special mention are the pickup coil, the
transistors, and the transformers.
The transistors are general purpose
PNP types and several alternative type
numbers are given in the circuit. At least
one of these types should be readily
available.
Pickup coils will probably be available
from Tandy as a separate item, but we
found them available in at least two other
Sydney stores: Radio Despatch Service
and Dick Smith Pty Ltd. We imagine they
would be as readily available in other
states.
The same two store* should also be
able to supply transformers. The output
transformer should have a centre tapped
primary with an impedance of around
400 to 500 ohms and an 8 ohm secondary.
The driver transformer should have a
primary of about 2500 to 3000 ohms, with
a similar secondary, centre tapped.
Construction should not present any
serious problems. As we said earlier,
layout is not critical and so it may be built
in almost any form. A piece of Veroboard
would probably make a good substitute
for the plastic box. $
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ELECTRONICS Australia, December, 1976
51
Versatile new design offers several options:
Modular Digital Clock
Here is our simplest-ever digital clock project. In its basic form, all that
is required is a clock module, a transformer, two switches and a case.
But if desired it can be expanded to include alarm, snooze, sleep and by DAVID EDWARDS
radio switching functions.
At the heart of this new digital clock
is a new clock module recently released
by National Semiconductor. Designated
the MA1002 LED display electronic clock
module, it is available in eight different
versions. Current retail price of individual
modules is currently around the $14.00
mark.
Each module consists of a monolithic
MOS-LSI integrated clock circuit, four
digit 13mm LED display, power supply
and other discrete components, all
mounted on a single printed circuit
board. Perhaps the most unusual feature
of the assembly is that both the clock
chip and the display LEDs are mounted
directly onto the circuit board, without
the use of conventional 1C packages.
As you can see in the accompanying
photographs, the clock chip is centrally
mounted under a blob of epoxy. The
LEDs are mounted on the other side of
the board, and protected by a red plastic
lens, which also serves to provide optical
magnification for them.
There are only fifteen other discrete
components on the board, and these are
dominated by a power transistor and its
associated heat sink. The overall size of
the complete module is a tiny 77 x 35 x
17mm.
All that is required to turn the module
into a functioning clock is a mains trans¬
former and switches, as well as the usual
mains lead and mounting hardware.
Eight different modules are available, and
these are distinguished by suffixes A to
H. Modules A, C, E, and G, are all
intended to operate from 60Hz mains
supplies, and are not of much interest to
us at this stage.
Modules B, D, F and H are the 50Hz
versions. Types B and F have a 12 hour
display (with PM indication) while types
D and H have 24 hour displays. Types B
and F are intended as dock radios, while
types D and H are intended as alarm
clocks.
All modules have alarm facilities,
incorporating a nine minute ’"snooze"
delay. This turns off the alarm for nine
minutes, and then sounds it once more.
This process can be repeated for an hour
(by which time you will be very late for
work!).
Provision is made for varying the
display intensity, either manually or
automatically (using an LDR or similar
•device). There is also a sleep output
which allows a radio or similar device to
be turned off after a programmable delay
of up to 59 minutes.
Let us consider first the alarm clock
versions (F and H). These versions incor¬
porate an additional small signal transis¬
tor, connected as an oscillator controlled
F'G i BASIC CLOCK
ELECTRONICS Australia, December, 1976
The circuitry shown at left is all
that is required to make up the
clock in its most basic form.
The basic clock module can
be purchased with either a 12
or a 24 hour display.
by the alarm output of the clock chip.
This oscillator is intended for use with a
low cost earphone audio transducer,
which must have a resistance of 500
ohms and an inductance of lOOmhl.
All that is required to build an alarm
clock .with snooze facilities is this ear¬
piece, along with the clock module,
transformer, case and switches. Con¬
struction is reduced to mounting the
various parts in the case, and wiring them
together.
Note that the sleep facility is included
with the alarm clock versions, so that if
desired, a radio or similar appliance can
be controlled by the clock as well. This
is done in the same way as for the clock
radio versions, which will be described
next.
The clock radio versions (types B and
F), differ from the alarm clock versions
only in that the alarm oscillator is not
included. However, the alarm output is
still available, so that this can be used to
control a separate alarm unit.
The most commonly available module
will be the B type (12 hour 50Hz clock
radio), so our discussions from now on
will centre on this type. The other types
of module are essentially similar, so that
the circuits to be presented can be used
with them.
Fig. 1 shows the basic clock circuit. A
transformer is required with two secon-
■ dary windings, connected as shown. The
16V winding should have a current rating
of at least 25mA, while the centre-tapped
10V winding should be able to supply up
to 250mA. One end of the 16V winding
is connected to the centre tap of the 10V
winding.
The 16V winding is used to power the
clock chip itself, while the other winding
supplies the display LEDs. This reduces
the dissipation in the display drivers. The
display is driven directly (i.e. it is not
multiplexed), so that radio interference
is reduced.
y . ■ ■■ ■ ■ . . .
I
Fig. 2 (above) shows the location of the various connection points on the clock
module. Exercise due care when soldering to the board , as discussed in the text.
To implement the basic clock, only
two switches are required. These should
be momentary contact types, and are
used to set the time. They are connected
as shown between pads 2, 5 and 6 of the
module, with a link connected also be¬
tween pads 3 and 4.
When power is first applied, the
display will show some random time, and
it will be flashing at a 1Hz rate. This is
the power failure indicator. When either
of the time setting switches is operated,
the display will remain steady, with the
colon flashing at one second intervals.
This shows that the clock is counting, and
also gives some indication of the passage
of seconds.
PM indication is by means of a small
dot in the upper left hand corner of the
display. When this is illuminated, the
clock is in the PM phase.
Fig. 2 shows the location of the various
connection points on the clock module.
If desired, this simple clock can be
assembled, either for use as it stands or
preparatory to adding the more exotic
functions, such as the alarm and radio
features.
Turning now to Fig. 3, we can discuss
the full feature clock. Switches SI, S2, S3
and S4 are all momentary contact types,
and control respectively setting of the
time, setting of the snooze, and seconds
display facilities. When this latter switch
is operated, the display shows minutes,
tens of seconds, and seconds.
Switch S5 is a single pole toggle switch,
and serves to turn the alarm facility on
and off. When this switch is in the on
position, a small dot in the right hand
bottom corner of the display is illumi¬
nated.
Switch S6 is a three position toggle
switch, with a centre off position. This is
used to enable the time setting switches
PARTS LIST
BASIC CLOCK
7 National Semiconductor MA1002B
clock module (see text)
7 transformer , 240V to 16V and
10VCT (A & B 9827, j.T. 197 or
similar)
2 momentary contact switches
1 case , see text
2 aluminium clamps , see text
Solder , hookup wire , machine screws ,
mains cord , cord clamp , grommet
terminal block
EXTRA PARTS FOR FULL FEATURE
CLOCK
1 printed circuit board , coded 76cl12,
measuring *76 x 50mm
1 BC54B NPN transistor
2 BC558 PNP transistors
1 C106Y1 SCR, or BRY39 SCS, or
similar
2 EM 401 silicon diodes
1 IN 91 4 silicon diode
1 3.6V 400mW zener diode
1 ORP12 light dependent resistor
1 22k trimpot
1 10M, 1 100k, 3 10k, 1 6.8k, 1 Ik 'AW
resistors
1 470uF 25VW PCB mounting elec¬
trolytic capacitor
1 IOOuF 10VW PCB electrolytic
capacitor
3 SPST miniature toggle switches
1 SPDT centre-off miniature toggle
switch
1 alarm unit, see text
1 radio unit, see text
Tinned copper wire, rainbow cable ,
machine screws
NOTE: Resistor wattage ratings and
capacitor voltage ratings are those
used for our prototype. Com¬
ponents with high ratings may
generally be used provided they are
physically compatible.
to set the alarm time and the snooze time
as well.
Automatic variable intensity of the
display can be added quite simply, as
shown. All that is required is a 22k trim-
pot, and an ORP12 LDR (light dependent
resistor). These are connected in parallel,
and inserted in the link from pad 3 to pad
4.
The next additional feature >we have
provided is a touch switch to allow con¬
venient activation of the snooze facility.
This is based on the Proximity Switch
presented in the November 1976 issue by
fellow staff member Leo Simpson. We
have amended his circuit considerably,
as our requirements were different, and
this has reduced the component count.
Our circuit uses a silicon controlled
rectifier (SCR), one BC558 transistor, and
four resistors. The cathode of the SCR is
connected to one end of the 16V second¬
ary winding via a 6.8k resistor. The anode
ELECTRONICS Australia, December, 1976
53
is connected to pad 2 of the clock
module via a Ik resistor.
Pad 2 is connected to pad E8 by the
wiring on the PCB, so that an AC wave¬
form is applied across the SCR. When a
hand or similar object approaches the
touch plate, the increased capacitance
triggers the SCR, which then conducts on
every alternate half cycle.
The current pulses through the SCR
also flow through the Ik resistor, and
thus turn the transistor on. The collector
of this transistor is connected to the
snooze input, pad 8, and thus shorts this
pad to pad 2.
Since the transistor is being turned on
and off once in every mains cycle, this
has the effect of operating the snooze
facility at the same rate. This does not
affect the snooze operation, but does
affect the display.
This is because operation of the
snooze switch also changes the display
from normal time to the alarm time, so
that the display alternates between the
two at a 50Hz rate. The visual effect of
this is that the two times are combined,
producing strange displays like 4 : 98
(from 4 : 46 and 1 : 31).
However, as this only occurs for the
short time when one's hand is covering
the touch plate, we felt that it was not
objectionable, and did not warrant extra
components to eliminate it.
The remaining features we have added
are the alarm and radio drivers. These
derive their power supplies from the 10V
winding, via two silicon diodes and a
470uF electrolytic capacitor. Each circuit
uses a BC548 transistor, to buffer the out¬
puts from the clock module.
The alarm circuit uses the transistor as
a switch, with the load formed by the
alarm itself in the collector circuit. The
1N914 diode prevents the base-emitter
junction from being reversed biased. The
alarm unit can be a solid-state buzzer of
the type available from Dick Smith Elec¬
tronics Pty Ltd, or a Sonalert or similar
device. Alternatively, a multivibrator
could be used to drive a small speaker.
The important requirements of the
alarm unit are that it should operate from
a 6V DC supply, and that its current drain
should be fairly ^mall, in the order of
20mA or so.
The radio circuit uses a switched
regGlated power supply to provide a
nominal three volts to the radio. This is
achieved by using a 3.6V 400mW zener
The photograph at left shows all the components needed to
make up the basic clock circuit. Below is the PC board pattern
for the full feature clock , reproduced actual size.
54
ELECTRONICS Australia, December, 1976
diode to stabilize the base voltage of the
transis.tor. If higher supply voltages are
required, a higher valued zener can be
used.
The supply is switched on &nd off by
supplying the zener current directly from
the sleep output of the clock module, via
a 10k resistor. If a manual switch is
required, this can be added by connect¬
ing the cathode of the zener diode to the
0V rail (pad E8 or pad 2), via a suitable
switch and another 10k resistor.
If a considerably higher supply voltage
is required for the radio, say 9V, then it
will be necessary to use the 16V winding
for this. This will require one extra diode
and filter capacitor, which must be con¬
nected between pad E6 and pad E8 so
as to produce a negative voltage with
respect to pad E8.
A 10V zener would then be required,
with the anode returned to the new
negative rail, along with the negative
radio terminal. Note that the current
drain which can be taken from this wind¬
ing is reduced compared to that available
from the 10V winding.
Note also that as we have drawn the
circuit, the alarm and radio circuits are
quite distinct. If it is desired to dispense
with the alarm, and use the radio as an
alarm as well, then the alarm sections can
be left out, and pad E3 connected to the
10k resistor used for the manual radio
switch.
Construction of the clock is very easy,
and should be within the capabilities of
most readers. We used one of the plastic
cases from A & R Soanar, measuring 140
x 85 x 130mm. These are of modular con¬
struction, and are supplied with a plastic
front panel and a metal rear panel. They
are available in a variety of colours.
As you can see in the photographs, we
mounted the transformer and associated
components on the rear panel, and the
clock module on the front panel. This
was achieved by making a rectangular
cutout in the plastic, for the display lens,
and pushing the module through from
the rear. It is held in place by two small
brackets clamped behind the two front
panel switches.
Details of the brackets are given in a
diagram elsewhere in the article. We
used small pieces of foam rubber be¬
tween the clamps and the module, and
between the module and the panel. This
gave a firm mounting, without damaging
the module.
For the basic clock, all that remains to
be completed is the wiring between
switches, the module and the transfor¬
mer. We used small momentary contact
pushbutton switches for the basic clock,
and completed the wiring with short
lengths of colour coded hookup wire.
At this stage, it is appropriate to cau¬
tion readers that some of the pads on the
module are connected directly to the
clock chip, which is a MOS device, so
that caution with regard to static voltages
is required during assembly. The module
is supplied with a conductive strip joining
10M 100k TOUCH
FIG 3
4
MODULAR DIGITAL CLOCK
The circuit diagram for the full feature clock. Note that snooze
if the optional touch plate circuitry is incorporated.
7/CL/-
s witch S3 is deleted
pads 1 to 11, and this should not be
removed till the last moment.
Your soldering iron should be earthed,
and connected to the positive side of the
IOOuF electrolytic capacitor on the rear
of the clock board. The wires should be
joined to the module by inserting their
stepped ends in the relevant holes, and
quickly soldered, using a minimum of
heat and solder.
Testing simply consists of applying
power and checking that the clock
operates correctly. When power is first
applied, the display should flash at a one
second rate. This should stop when
either of the time setting switches is
operated.
In order to simplify construction of the
full feature clock, we have designed a
small printed circuit board, coded
76cl12, and measuring 76 x 50mm. This
board accommodates the circuitry for
the alarm and radio driver circuits, as well
as for the touch switch.
This is mounted on the bottom of the
case, using the four corner holes
provided, and connected up to the trans¬
former and module with colour coded
Component overlay on the
PC board for the feature
clock. Use circuit board pins
to facilitate external connec¬
tions.
MANUAL RADIO
E6 E7 E8 E9
«H 10** :
iok _}■»£ 8 (•
H — 1+H
•♦8C548
, ♦£ 1N®14
C £ BSBC548
r-r A#2 mr #BC558
6W>* s.5 5 «c
10M ♦‘I Ik
iPOkT* ♦
TOUCH PLATE PA° 8
ELECTRONICS Australia, December, 1976
55
FLUKE PROVES AN INEXPENSIVE,
HANDHELD DMM
CAN BE BUILT WITHOUT LEAVING
EVERYTHING OUT.
The Fluke 8030A is a new breed of digital multimeter.
It’s not like earlier DMM’s that were small, but had nothing
to offer. Instead, the 8030A has all the performance, features,
accuracy and resolution you would expect from a benchtop
instrument at a much higher price.
It’s an inexpensive, handheld 3!/2-digit DMM. But it’s also
built to Fluke standards and Fluke quality. That makes the
difference.
\The 8030A DMM is designed for use by troubleshooters
and field service technicians. It offers six measurement func¬
tions in 26 ranges. Automatic polarity and automatic zero
suppression are standard. Rugged construction. Small size.
Accuracy specifications that are guaranteed for a year. Plenty
of accessories. Even a built-in hood that pulls forward for
easier reading in sunlight.
But the most important news about the 8030 A is all the
features we’ve designed into it.
Measurement
The six measurement functions are ac volts (true rms),
dc volts, ac current (true rms), dc current, resistance, and
diode test. Each function has five selectable ranges, except
diode test which has one.
distorted wave forms. AC coupling rejects dc bias during
ac voltage measurements. And dc coupling on ac current
ranges provides ac + dc capability for measuring power supply
and SCR regulating circuitry.
In-Circuit Resistance
In circuit resistance measurements can be made using all
five resistance ranges. Errors due to effects of parallel semi¬
conductor junctions are avoided by applying a maximum
voltage of 200 mV across the on-scale unknown resistance.
Diode Test
The diode test function allows measu ement of diode and
transistor forward-voltage drops. A 1 mA bias current is forced
through the junction, and the resultant voltage drop is dis¬
played in millivolts. This function can be used for in-circuit
testing of transistors and diodes and will detect up to three
junctions in series.
Overload Protection
Extensive overload protection is provided, and, in addi¬
tion, units have successfully withstood transients up to 6,000V
across the input.
True RMS
True rms conversion techniques provide ac measurement
accuracy (voltage and current) in spite of noise levels and
Functional Self-Check
Each of the six measurement functions can be checked
for basic functional operation by using regular instrument
test conncections. No external test equipment is required.
EEMEASCO
Instrument * Pty. Ltd.
P-O. Box 30 Concord, N.S.W. 2137
736-2888
Melbourne: 233-4044; Adelaide: 42-6666
Brisbane: 36-5061
Perth. 25-3144.
ELECTRONICS Australia, December, 1976
56
Right: actual size reproduction
of the front panel for the basic
clock.
/
MODULAR DIGITAL CLOCK
SLOW SET
. MODULAR DIGITAL CLOCK
©
©
RADIO
SECONDS
hookup wire. Fourteen external .connec¬
tions to the board are required, and these
are best made with circuit board pins.
No difficulties should be experienced
in placing components on the board. If
you are using the BRY39 dual gate SCR,
cut off the anode gate (AG) close to the
device body, and then treat it as an
ordinary SCR.
If you do not wish to add all the fea¬
tures to the clock, simply leave out those
components not required. The LDR used
to control the display intensity can be
glued underneath one of the slots in the
0
©
SLOW SET
FAST SET
ALARM
ALARM ON
SET0
©
SLEEP
ALARM OFF
top of the case, with the trimpot soldered
directly across the leads.
We fashioned a touch plate from three
stout pieces of tinned copper wire,
fashioned into long staple-like shapes.
These were clamped across the case,
between the side slots at the front of the
case, and bent underneath to hold them
in position. At one end, they were bent
so as to touch, and the lead to the PCB
soldered on. Refer to the accompanying
photographs for more details.
We have not shown any mounting
details for the radio, as we felt that this
DIMENSIONS IN MILLIMETRES
Above: the metalwork diagram for the
two metal brackets. Make two from
scrap aluminium. Af left is an actual size
reproduction of the rear panel labelling
(feature clock only).
Left: actual size reproduction
of the front panel for the fea¬
ture clock.
was best left up to the individual con¬
structor. One possibility, however, is to
simply mount the radio on top of the
clock, so that all controls are still access¬
ible.
We have designed two front panels for
the clock, one for use with the basic ver¬
sion, and one for use with the more
advanced version. Both these are
reproduced full size with this article, and
they should also be available from the
usual metalwork suppliers as well.
We have been advised by National
Semiconductor that some of the latest
modules which have been imported are
supplied without heatsinks on the power
transistor. This is no cause for alarm
(sorry!) however, as the heatsink is
apparently only required n conditions of
high ambient temperature and display
brightness. If desired, a small heatsink
could be fashioned from aluminium, and
added to the transistor.
Type B clock modules, transformers
and associated parts are available from
Radio Despatch Service, 869 George
Street, Sydney, and from Techni-Parts,
Wool worths Arcade, 95 Latrobe Terrace,
Paddington (Qld.) 4064. This latter firm
also has type D, F and H modules, in
small quantities only, and earphone
transducers available. 3
ELECTRONICS Australia. December, 1976
57
University
Features of all University Multimeters.
1 . Specially manufactured to suit Australian conditions.
2. Overload protection fitted (double diode).
3. Heavy duty double jewelled precision movement.
4. Highest quality Alnico permanent magnet in movement.
5. Mirror scale with knife edge pointer for greater accuracy.
6 . Multicolour scale for ease of operation .
7. Anodised front label, permanent and attractive.
8. 4mm terminal sockets.
9. "OFF" switch position.
10. Unbreakable Polycarbonate Case.
MULTIMETERS
TEST INSTRUMENTS
Use the BEST-Specify UNIVERSITY
PRICE: . . HIGHEST QUALITY at the LOWEST PRICE
GUARANTEE: 90-day, backed by University after sales. service
SERVICE: . . . 24-hour efficient repair service
r
■
■
■
An ideal Christmas gift
for the enthusiast
l
l
l
.J
Automotive Analyser EA77
A must for the home mechanic to help
improve economy, performance and
efficiency of your vehicle.
Tacho: 0-1 200 and 0-6000 R.P.M.
suitable for 4, 6 and 8 cyl. engines
Voltage: , 0/3/ 1 5/30 Volt D.C.
Resistance: 0-1 OOohm (3 Kohm centre scale)
Dwell Angle: 0-45° for 8 cylinder.
0-60° for 6 cylinder.
0-90° for 4 cylinder.
0-90A(Ext. Shunt supplied)
Indication and neon light.
Price: $60.00
Available also in kit form
Current:
Spark Test:
Condenser
Sub:
0.22 ufd.
Complete with illustrated service manual.
Insulation Tester
Model F602
Solid State— Battery operated
Constant Voltages type circuit.
Compact, sturdy, lightweight.
Complete with carrying case.
Model
Insulation
Centre
Scale
Continuity
Voltage
Price
F602-500
0-100MQ
2MQ
0-1 00ft
500V
$72
F602-1 000
0-2000Mfi
50Mf2
0-1 OOfi
1000V
$84
Hand wound generator models are also available.
Clip-on Volt Ammeter Model MG-27
Pocket style Multirange Ranges.
Price $28
Volts: 0/300/ 600 Volts A C.
Resistance: 0-300 ohms
Amperes: 0/5/25/ 100— Model
MG27/100
0 / 1 0/50/250— Model
MG27/250
Maximum Cable size 30mm dia.
Complete with leads and case.
"De Luxe"
MVA-100CN
100K ohms per volt D C.
DCV: 0 5/2.5/10/50/250/1000V
AC V: 2.5/10/50/250/1 000V
DCA: 10uA/500uA/ 5mA/ 50mA/
500mA/ 10A
ACA: 10A
Res: Rxl , Rxl 0, Rxlk, RxlOk, RxIOOk
(.'1 ohm to 100M ohms)
db: -20/0/ + 62 db (Ref 1 mW in 600
ohms) /
Dimensions: 1 80x 1 40x80mm
Weight : 1.36 Kg.
Features: Polarity Reversing Switch
Price: $37.50
Digital Model-HM-35
DC Volts: 5 Ranges to 1 kV
AC Volts: 5 Ranges to 1 kV
DC Amps: 5 Ranges to 1 A
AC Amps: 5 Ranges to 1 A
Resistance: 6 Ranges to 20 Mfi
'Input Impedance: 1 0 Meg ohm all
ranges
Frequency Response: 1 0Hz to 20kHz
Automatic Polarity Indication,
Automatic Zeroing
Internal Battery Check
Over Range Indication
Compact & lighweight (420 gms)
Price: $150
including charger
"Popular Model'
CTN500MP
20K ohms per Volt D C.
DCV: 2.5 / 10/ 50/ 250/ 500/ 5kV
AC V: 10/50/250/500/1 kV
db: — 20/0/ + (5 ranges)
DCA: 50uA/ 5mA /50mA /500mA
Res: Rxl, RxlO, Rxl 00, Rxlk ohms
(1 ohm to 10M ohms)
Size: 150x110x50mm
Weight 450 gm
Price: $17.50
• Prices recommended trade price.
• Plus 1 5 pc Sales Tax and $2. 00 packing and post if applicable.
• All units are supplied with batteries, leads and instructions.
• Leather cases are available as an extra.
Please send to Mr
A comprehensive range of meters and test instruments may be inspected at our
Showroom and are available either direct from our Riverwood office, any leading
Wholesalers, or ordered on the enclosed coupon.
University Graham
Instruments Pty. Ltd.,
Qty . Model .
I enclose cheque/Postal Note for above unitor send C O D. Post to above.
EA-12-76
106 Bel more Road , RIVERWOOD
2210. Phone: 53 0644.
AUSTRALIA'S LEADING MANUFACTURER & IMPORTER OF
ELECTRICAL INSTRUMENTS
58
ELECTRONICS Australia, December, 1976
Auto Rhythm Unit
For Electronic Organs
In the previous article in this series, we gave details of how to use cn\A/Aonc
the M252 rhythm generator chip. This month we give details of the by DAVID EDWARDo
S8890 chip from American Micro-systems, and how to use it with the
instrument generator board.
The S8890 rhythm generator is a
counter-ROM specifically designed for
electronic organs and other electronic
instruments. It is supplied in a 40 pin DIL
ceramic package, and contains an internal
oscillator, a 6 bit counter, and a ROM that
drives eight instruments, as well as a
seven-segment sequence count display.
The S8890 chip is obtainable from
Cema Distributors Pty Ltd, 21 Chandos
Street, Crows Nest NSW 2065. Your usual
component supplier should be able to
obtain it for you.
The oscillator frequency is determined
by an external network, and requires the
addition of only a PNP transistor, two
capacitors and three resistors. The 6 bit
counter has inputs that allow the counter
to be reset at any one of five counts. The
64th count is normally programmed as
the fifth reset option.
The counter contains a start input that
holds the system in the reset mode until
a start command is impressed. The coun¬
ter outputs drive a 64 word ROM, which
has eight rhythm instrument outputs, a
downbeat output, and a rhythm count
output.
The downbeat output is programmed
to provide an output at the beginning of
each measure. The eight instrument out¬
puts each contain 10 rhythm patterns
which may be simultaneously selected to
overlay multiple rhythm patterns.
The rhythm count outputs provide a
seven segment code that can be used as
a visual display of musical timing. We
have not included this feature in our
rhythm generator, as we felt that it was
not essential to the production of
rhythms. Information on how to use this
feature can be obtained from the S8890
data sheet.
Turning now to the circuit diagram, we
can discuss the various features of the cir¬
cuit. As before, a buffer is required for
the power supply from the instrument
generator board. This has been
implemented in an identical manner, and
need not be discussed here.
The oscillator is formed by the second
PNP transistor and its associated com¬
ponents. The 22uF tantalum capacitor is
charged via the 22k tempo control and
the associated Ik stopper resistor. The
capacitor voltage is monitored by pin 16,
and when this exceeds an internal
threshold, pin 17 turns on the transistor,
which discharges the capacitor. The
cycle then repeats.
Pin 18 is connected to the + 30V rail
via the reset switch. This resets the coun¬
ter, which commences from the start of
the program when the reset switch is
released.
The downbeat output is connected
directly to the downbeat input of the
instrument generator board. This must
be wired to accept positive edge trig¬
gering. The downbeat LED will then
operate at the start of every measure.
The eight instrument outputs are also
connected directly to the inputs of the
instrument generator board. Since the
outputs consist of a single transistor con¬
nected to the -I- 30V rail, it is not neces¬
sary to use the input diodes of the
instrument generator. These may be
replaced with links.
Pins 21 to 30 are the rhythm select
inputs. Pins 10, 11 and 13 must be con¬
nected to pins 25, 26, 27 and 29 as shown.
These latter pins are the count reset
inputs, and are used to reset four of the
rhythms at counts which are less than the
maximum count.
The two diodes are necessary to
prevent interactipn between the two
rhythm select inputs which are con¬
nected to pin 11. As stated earlier, only
ten separate rhythms can be obtained
from the S8890 device, but more than
one of these rhythms may be selected at
once.
We have used the same switch as
specified in last month's article, but have
re-arranged the wiring to suit the S8890.
The ten individual rhythms which are
selectable are as follows: waltz — shuffle
— jazz waltz — mambo — bossa nova —
march — swing — samba — beguine —
pop rock.
As before, the blank position does not
produce any rhythm at all. The remaining
five switch positions have been filled up
by combinations of the other ten
rhythms. For example, slow rock selects
both beguine and bossa nova.
In this diagram we have not shown the
output circuitry from the instrument
simulator board, because this is the same
as shown in last month's article. But to
aid construction, we have reproduced in
this article the Veroboard rhythm chip
wiring layout that we used for our proto-
MUTE fifsn
AUTO RHYTHM
mmm
he completed prototype provides for some fifteen different rhythms.
ELECTRONICS Australia, December, 1976
59
+ 30V
TO INSTRUMENT ,
GENERATOR BOARD “S
BASS DRUM-
SNARE DRUM-
TOM TOM-
LOW BONGO-
HIGH BONGO-
MARACAS-
SHORT CYMBAL-
LONG CYMBAL-
^2
(POSITIVE EDGE
TRIGGERING)
\ +
* TANTALUM
L
i
27
-(Eh. AUTO RHYTHM (S8890 RHYTHM CHIP)
y 1/EM/.
nr
iO
RHYTHM
SELECT
• u
WALTZ/SHUFFLE
fc4
JAZZ WALTZ /MAMBO
U
SLOW ROCK/BOSSA NOVA
MARCH/CHA CHA
m
i
SWING/BAJON
1
FOXTROT/SAMBA
TANGO /BEGUINE
BLANK/POP ROCK
I
In
F
DETAIL OF COMMON
INTERCONNECTIONS
FOR ALL SWITCHES
type. This board will be a drop-in
replacement for the Veroboard used in
the previous article.
The S8890 is susceptible to damage
from static charges, and we recommend
that it be mounted ip a socket. All the
wiring to the instrument simulator board,
and the placing of the components on
the Veroboard can be carried out before
inserting the S8890 in the socket.
The circuit diagram shows a schematic
representation of the wiring for the
interlocked switches. This can be used as
a guide for wiring the switches. First
make all the connections to the centre
posts (shown on the diagram as the com¬
mon connections), and then complete
the remaining wiring on the switches.
Lastly, add the eleven wires connecting
the switch bank to the remainder of the
circuit.
Readers are referred to the previous
articles for details on a suitable case,
front panel, and component layout. The
parts list included with this article should
be read in conjunction with the one
presented in the October 1976 issue.
Once construction is complete, the
unit can be tested. Apply power, and
, check the operation of all switches and
controls. It may be necessary to adjust
the trimpots on the instrument board to
achieve suitable sounding instruments.
Follow the instructions given in the Octo¬
- BASS DRUM
►SNARE DRUM
► TOM TOM
-LOW BONGO
-HIGH BONGO
-MARACAS
-SHORT CYMBAL
-LONG CYMBAL
-30 ^
-29
-28
-27
-26
-25
-24
- 23
-22
-21 .
TO 8 WAY
> INTERLOCKED
SWITCH
(The circuit diagram at top shows how the S8890 rhythm chip is interfaced to the
player and to the instrument simulator board. Above is a component overlay pattern
for making the circuit up on a small piece of Veroboard.
ber article for this. ’
As before, we found that it was neces¬
sary to change one resistor on the
instrument board to achieve a more
realistic sound balance. We altered the
1M resistor connected to the 0.1 uF
capacitor at the input of amplifier B2 to
100k. Note that we did not alter the feed¬
back resistor, but the resistor connected
to the FET source-
in order to give an improved sound
when rapid tempos are used, we found
it advantageous to alter the time con¬
stants of the white noise derived
60 ELECTRONICS Australia, December, 1976
instruments. This can be achieved in
several ways.
The time constants of each of the final
R/C combinations connected to the FET
gates must be reduced in value by a fac¬
tor of about four. This is done by reduc¬
ing either the resistor or capacitor
values.
Economically, the best solution is to
reduce the capacitors, from 0.47uF to
0.1 uF, and from 0.22uF to 0.047uF.
However, if you have already purchased
these capacitors, then it may be cheaper
to replace each of the trimpots with suit¬
ably lower values.
PARTS LIST
7 S8890 rhythm generator chip
2 BC558 PNP transistors
1 18V 400m W zener diode
3 IN 91 4 silicon diodes
7 22uF tantalum electrolytic capacitor
7 0.47uF tantalum electrolytic
capacitor
3 0.1 uF plastic capacitors
1 390 ohm, 7 7k, 7 75k, 7 56k VaW
resist ors
1 22k linear potentiometer
1 47k dual log. potentiometer
3 NKK DPDT toggle switches , part
No. SP2022
3 NKK bezels to suit , black , part
No. AT -205
1 Schadow 8-way 4-pole interlocked
push button switch , part No.
TS-539
MISCELLANEOUS
2 Knobs
1 case , 230 x 205 x 68 mm
1 front panel to suit , see text
1 PL24/20VA 24V transformer ,
or equivalent
1 piece Veroboard (1/10" spacing)
1 output connector
Solder , hookup wire , rainbow cable ,
shielded cable , PCS standoffs , rubber
feet
Note: resistor wattage ratings and
capacitor voltage ratings are those
used in our prototype. Components
with higher ratings may generally be
used provided they are physically
compatible. Components with lower
ratings may be used in some cases ,
providing ratings are not exceeded.
Reduce the 2.2M trimpots to 470k, and
the 1 M one to 220k. A third alternative,
which is cheaper but less desirable, is to
simply add extra resistors in parallel with
the existing trimpots, on the underside of
the board.
We have been unable to present
details of how to use the S2566/S2567
combination rhythm generator chips, as
we were unable to obtain sufficient data
about these devices in time to meet the
deadline for this article. The lack of a
sample of the M253 device has also
prevented us from supplying details of
how this device can be used. $
When hismini'Computer,one day,
refused to compute, Alvin was in
strife. . .THEN he remembered !
Alvin's one of those self-styled
electronic wizards, totally
dedicated to his hobby — his
array of expensive equipment .
assembled over the years is
proof positive. Fie knows that
electronic equipment requires
dust and moisture-free atmos¬
pheric conditions for maximum
efficiency, and so,, when, one
day, his pride-and-joy mini¬
computer refused to compute,
he knew what to do . . . damp
contacts, dusty computer
heads, contaminated points
. . . spray with CRC CO
Contact Cleaner — lifts, dis¬
solves, evaporates completely,
effectively, immediately, all
residual contaminants and
moisture. No disassembly of
complicated units, no expen¬
sive parts to replace . . . just
a simple application of an
incredible product like CRC
CO Contact Cleaner to
“dissolve" the problem. If
you're a dedicated “Alvin" too,
you'll want to try CRC CO
Contact Cleaner yourself. Ask
for it at your nearest electrical/
electronics retailer, or for
more info about it write to:
CRC Chemicals Australia Pty
Ltd, Centre Court, Paul Street,
North Ryde, NSW, 2113
THE SOLUTION SOLUTION
CRC CHEMICALS AUSTRALIA PTY. LTD.
Centrecourt, 25-27 Paul St., Nth. Ryde 2113. Phone: 888-3444
ELECTRONICS Australia, December, 1976
61
A practical, down-to-earth introduction to
t
Op-Amps without tears- 1
Here is the first of a short series of articles which provide a practical,
down-to-earth introduction to modern operational amplifiers and their
applications. If you're still not too familiar with these powerful little
devices, it should make rewarding reading. by J. BRIAN DANCE, M.SC
The operational amplifier is the most
important basic building block of all
linear circuits. It has a wide array of
applications in such fields as audio
power amplifiers, timers, voltage regula¬
tors, sensitive measuring circuits, etc.
This series of articles will provide readers
with a basic understanding of the opera¬
tion of these units (even if they have had
no previous experience whatsoever).
The basic principles will be covered in
the early parts, but the emphasis will be
on the practical use of the devices in cir¬
cuits rather than on the internal circuitry
of the devices used.
THE BASIC AMPLIFIER
The term 'operational amplifier' was
originally applied to high gain amplifiers
operating down to zero frequency which
were used in analog computers to per¬
form certain mathematical operations
(including addition, subtraction, integra¬
tion, etc). These high gain amplifiers are
now used for a wide variety of applica¬
tions, but the name "operational ampli¬
fier" or "op amp" is normally used even
though no mathematical operations are
involved.
The early operational amplifiers em¬
ployed discrete components, but it is
now much more convenient to employ
an integrated circuit. Instead of making
up a circuit containing perhaps a
hundred discrete components, one uses
a small integrated circuit together with
perhaps half a dozen external compon¬
ents. The integrated circuit or 1C contains
a large number of individual components
all formed on a miniature silicon chip. All
of the connections between the internal
components are automatically made by
photographic techniques during the
manufacture of the 1C.
One of the main advantages one
* obtains from the use of integrated cir¬
cuits is the saving in time wiring up
numerous connections, but an additional
advantage is that the internal connec¬
tions are much less likely to fail during
use than connections made by a solder¬
ing iron. One also saves a great deal of
space and weight by the use of integra¬
ted circuits instead of discrete com¬
ponents.
Another advantage of using integrated
circuits is that the cost of most of the
commonly used devices is far less than
the total cost of the components in an
equivalent circuit using discrete com¬
ponents. Indeed, some modern integra¬
ted circuits containing many transistors
are priced at a value only two or three
times the cost of a cheap transistor.
A minor disadvantage of an integrated
circuit is that one cannot make any
changes to the internal circuit contained
in the device, since the components are
fabricated on a monolithic silicon chip
which must be carefully sealed against
the moisture and other substances in the
atmosphere.
Integrated circuit operational ampli¬
fiers are best regarded as building blocks
which can be used to assemble more
complex circuits. These devices are now
so convenient to use that very few peo-
NON INVERTING
INPUT
INVERTING
INPUT
FIG 1
POSITIVE
SUPPLY
pie even consider the construction of a
complete discrete amplifier unless there
are special circuit requirements.
The circuit designer is not generally
interested in the internal components of
an integrated circuit, but only in the per¬
formance of the unit as a whole. One
therefore uses the amplifier symbol in
Fig. 1 to denote the amplifier. It can be
seen that there are two inputs, one out¬
put and connections to the positive and
negative supply lines.
If one makes the inverting input slightly
more positive, the output will become
more negative; this is why the name
'inverting' is given to this input. If, how¬
ever, the non-inverting input is made
more positive, the output will also
become more positive.
THE 741
We shall start our discussion with
special reference to the 741 device, since
it is one of the best known general pur¬
pose operational amplifiers and is readily
available from almost all of the large
semiconductor manufacturers. If is also
one of the cheapest of all linear integra¬
ted circuits.
The user meets only the external cir¬
cuit, so one of the first questions the
newcomer to electronics will ask is
"What does a 741 device look like?". The
device is actually available in a number
of different packages, some of which are
shown in Figs. 2 to 4, with connections.
Readers will usually find the type of 741
shown in Fig. 2 the most convenient to
use; it is also normally the cheapest. This
type of package is known as the 8 pin
dual-in-line, since there are four pins on
each side of the body of the device and,
when viewed from one end, these pins
form two lines of four pins per line.
The triangular symbol for an amplifier
is drawn on the body of the device in Fig.
2 for clarity. As in all dual-in-line integra¬
ted circuits, there is either a small notch
between pins 1 and 8 or a small circle
near to pin 1 which identifies the end of
the device near to pin 1. The user must
be careful that the device is used the cor¬
rect way around and it is only these small
marks which provide this information.
An electrically similar 741 device can
also be obtained in the 14 pin dual-in-line
package shown in Fig. 3. Yet a further
type is in the circular metal "TO-5"
transistor-type package of Fig. 4. Other
more expensive packages are available,
OFFSET NULL 1|
INVERTING INPUT 21
NON-INVERTING INPUT 31
NEGATIVE SUPPLY 4 1
FIG 2
but the cheapest ones are usually
adequate for most of the non¬
professional requirements.
SOCKETS
One can solder connections directly to
the 741 pins or one may solder connec¬
tions to a suitable socket and insert the
741 in the socket. Dual-in-line sockets for
the packages shown in Figs. 2 and 3 are
readily available, but may cost even more
than the device itself. Readers may
therefore prefer not to employ a socket,
but one should remember that it is much
D>x:
3 8 NC
37 POSITIVE SUPPLY
6 OUTPUT
3 5 OFFSET NULL
\
>
62
ELECTRONICS Australia, December, 1976
NC 1 C
easier to change a device suspected of
being faulty if one has used a socket.
Sockets are probably more attractive
with more expensive devices than the
741. To remove a device from a socket,
always slip a screwdriver blade under the
body of the device.
EXPERIMENT!
One of the best ways of learning about
any electronic device is to experiment
with it in simple circuits. This is especially
true in the case of operational amplifiers.
The circuit of Fig. 5 can be used to enable
the inexperienced reader to become
familiar with the 741 device.
It should be noted that positive and
negative power supplies are usually used
to pin 4. The non-inverting input at pin
3 is conventionally marked ' + ' and the
inverting input at pin 2 but these are
NOT the positive and negative power
supply connections. The capacitors Cl
and C2 may be required to prevent
instability if the power supply connec¬
tions are long, but one can often omit
these capacitors without any troubles
arising.
The voltmeter is connected to the out¬
put so that one can measure how the out¬
put voltage from the 741 varies as the
input voltages are changed. This meter
should have a full scale deflection of
about 10V, but a centre reading meter
(10V-0-10V) would be ideal.' One can, of
course, make a suitable voltmeter by
connecting a IOOuA meter in series with
a lOOkilohm resistor or a 1mA meter in
series with a lOkilohm resistor or some
similar combination.
OFFSET NULLING
The preset variable resistor VR3 is
included so that one can trim the circuit
so that the output voltage is zero when
the voltage at both of the inputs is zero.
This process is known as offset ‘null
adjustment. Connect both pins 2 and 3
to ground and adjust VR3 for zero output
voltage. Note that the adjustment is quite
critical. As the device warms up, the out¬
put voltage drifts off the zero, but it can
be returned to 2ero by adjusting VR3
again.
This drift of the output voltage with
temperature can be important when one
is using the amplifier at high gain. There
is no feedback in the Fig. 5 circuit, so the
amplifier is operating at maximum gain
where the drift with temperature is worst.
Indeed, this drift is one of the reasons
with the 741. In this circuit ±9V supplies
are shown, since readers can easily
obtain these by using two small batteries.
The supplies may be ±15V if larger out¬
put voltages are required but they must
never exceed ±18V with most 741
devices.
The pin connections shown in Fig. 5 are
applicable only in the case of the 8 pin
dual-in-line device of Fig. 2 or of the cir¬
cular metal package of Fig. 4. The con¬
nections for the 14 pin dual-in-line
package are quite different, as shown in
Fig. 3. It should be noted that the -t-9V
supply is fed to pin 7 and the — 9V supply
why operational amplifiers are not nor¬
mally used in this way.
GAIN
The gain of an operational amplifier is
generally extremely high, but varies con¬
siderably from one device to another. For
example, the gain of the 741 at zero
frequency is quoted as being typically
200,000 in most, manufacturers' data
sheets, with a minimum for any one
device of 20,000 or 25,000 and no
maximum value quoted.
One can make an estimate of the zero
frequency gain of a 741 device using the
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ELECTRONICS Australia, December, 1976
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ELECTRONICS Australia. December, 1976
Op-Amps without tears
input circuit shown in Fig. 5. The value
of R1 should be about 50 kilohm when
the 741 has a gain near to the minimum
value of 20,000 but a value of 2 megohm
is more suitable for 741 devices which
have a high gain. When R1 has a value
of 50 kilohm, the potential at the junction
of R1 and R2 will be about 400uV; if this
is amplified 20,000 times, one obtains a
convenient reading of about 8V on the
output meter. If, however, R1 has a value
of 2 megohm, the junction of R1 and R2
will have a potential of about 9uV; this
is suitable for use with a device of a gain
of nearly one million to produce a suit¬
able output voltage reading.
A value of about 500 kilohm may be
tried initially for R1. After setting the off¬
set null voltage to zero at the output,
leave the inverting input grounded and
move VR1 so that the non-inverting input
is connected to the potential at the junc¬
tion of R1 and R2. If the voltage reading
at the output is too small to be conven¬
iently read, decrease R1, whilst if the
reading is above 7V R1 should be
increased.
When a suitable value of R1 has been
found, note the change in the output vol¬
tage reading as the non-inverting input
is moved from ground potential to the
junction of R1 and R2 by means of VR1,
VR2 remaining at ground potential
throughout. The voltage gain is equal to
this change in output potential divided
by the change in the non-inverting input
potential, the latter being approximately
equal to R2/R1 multiplied by 9V.
Note that as the potential of the non¬
inverting input is increased slightly, the
output voltage increases, whereas an
increase of the inverting input potential
will result in a decrease in the output vol¬
tage. If the sliders of both VR1 and VR2
are moved from the lowest (ground)
potential to the highest potential (at the
junction of R1 and R2), the output vol¬
tage will show little change, since the
increase in potential of the one input is
almost exactly balanced by the increase
in potential of the other input. Thus the
circuit is essentially sensitive to the dif¬
ference between the potentials of the
two inputs.
If one keeps the ^inverting input poten¬
tial at ground and varies the non¬
inverting input voltage by VR1, the
output voltage varies as shown in Fig. 6.
It should be noted that the maximum
possible swing of the output voltage is
about IV.Iess than the potential of either
supply line-hence the horizontal parts of
the graph of Fig. 6.
AC GAIN
If an audio signal generator and either
an oscilloscope or an AC voltmeter is
available, the gain of a 741 device can be
measured at various frequencies. A suit¬
able circuit is shown in Fig. 7, the offset
nulling potentiometer being unnecessary
in this application. The output voltage
can be measured by means of an oscillo-
gain falls off in a similar way with
frequency when the signal is fed to the
inverting input.
FEEDBACK
We have seen that the 741 device
offers a very high gain at low frequencies.
However, this gain varies so much from
device to device that we could not even
specify definite values of the resistor R1
in Figs. 5 and 7. The gain falls off above
about 5Hz at approximately 20dB for
each factor of ten increase in frequency
and the quiescent output voltage varies
widely even with small temperature
changes.
The reader may well question whether
a device with so many disadvantages is
likely to be of any practical use. We shall
see in the next article that the answer to
scope or a suitable AC voltmeter, care
being taken that the input is not so high
that the output approaches the horizon¬
tal parts of the Fig. 6 graph. The alternat¬
ing input voltage is best measured by
connecting the oscilloscope or AC volt¬
meter across the audio generator and
dividing by the ratio R1/R2.
Thus the gain of the amplifier can be
found by simply dividing the alternating
output voltage by the alternating input
voltage. It will be found that the gain of
a 741 device falls off quite rapidly 3t
frequencies above about 5Hz; this varia¬
tion of gain with frequency is shown in
Fig. 8 for a typical 741 device. It may be
noted that the gain falls to zero at a
frequency of the order of 1MHz.
The bandwidth of the amplifier is nor¬
mally taken as the frequency at which the
gain has fallen by 3dB. This is the
frequency at which the output voltage
has fallen to Mil ox 0.707 of its gain at
very low frequencies. The .experiment
may be repeated with inputs 2 and 3
interchanged in order to check that the
these problems lies in the use of negative
feedback. Such feedback does reduce
the gain, but it can allow the gain to
become dependent only on the values of
two external resistors, so that variations
from device to device have a negligible
effect on the performance. The gain can
be made constant up to much higher
frequencies than 5Hz, but it inevitably
falls at some value of frequency and con¬
tinues to fall as the frequency is further
increased. The offset voltage still exists,
but with a circuit of lower gain the drift
of the output voltage becomes tolerable
for most applications.
Operational amplifiers are rarely used
in practice without negative feedback.
The problems we have encountered are
just unacceptable in almost all applica¬
tions. However, we have not wasted our
time looking at circuits without feed¬
back, since the understanding we have
gained will help us when using the
• devices. We are now aware of many of
their limitations.
The gain we have been measuring is
known as the "open loop" gain, since it
is the gain measured with the feedback
loop "open" (that is, with no feedback).
(To be continued.)
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$3.00 plus 60c p & p
Electronics Australia
Box 163, Beaconsfield, NSW 2014
. ELECTRONICS Australia, December, 1 976
65
Forum
Conducted by Neville Williams
Is 2-chan net stereo the pure system?
As usually happens when an audio subject is brought up, our discussion
in the September issue about the implications of the word "stereo"
attracted more than its share of attention. Some readers confessed that
they had never thought it through before; some couldn't understand
what all the fuss was about; some agreed, others disagreed with the
various points of view.
From across the Tasman came a letter
from F.S. of Papatoetoe, New Zealand,
who writes thus:
Dear Sir ;
Do you not think that you have been
rather harsh on R.P. who seems to ask
a reasonable question regarding the
technical aspects of stereo ? While the
article's contents are of interest on the
broad subject ; it does not seem to con¬
tradict or comment on R.P.'s statement:
"It is fundamental that there be two
effective channels right through the chain
for all sounds".
Is this statement correct ?
In supporting the use of multiple mono
recordings to build up a stereo record ,
you imply that it is not correct but I think
readers are entitled to a clearer explana¬
tion.
Have you ever made a direct com¬
parison between recordings of, for
example, two instrumentalists some dis¬
tance apart with individual microphones,
and two instrumentalists together with a
Blumlein pair ?
First let me say that, if guilty of treating
R.P. harshly, I am more than ready to
apologise. We certainly do not seek to
take unkind advantage of readers who,
in all good faith, raise matters for discus¬
sion in these columns.
Of course, if a correspondent
obviously wants to "have a go", we may
tend to reply in kind, but there was no
such suggestion in R.P's letter or, I hope,
in our reply.
However we— or l^-clearly stand
accused of not being sufficiently explicit;
of making the discussion so wide ranging
that the key question was answered by
implication rather than in so many words.
Rather than becoming involved in
semantics, let me spell out the answer
right here:
Most definitely, normal domestic
stereo relies on signal information from
66
two separate channels to position the
apparent sound sources.
When the signal from both channels is
identical in amplitude and phase, the lis¬
tener will normally perceive an apparent
sound source at centre front, indistin¬
guishable in itself from a mono source.
If the relative balance between the sig¬
nals is changed, the source will move to
left or right, just as if it were being
reproduced in the new position by a sin¬
gle loudspeaker. In fact one of the cri¬
teria for judging a stereo system is its
ability to create "firm" mono images
When handling typical program
material, the balance between channels
varies subtly for each individual sound
source so that, at the listening end, virtual
point-source images are spread across
the listening "sound stage". In other
Is this the microphone hifi purists should
really be backing— the tetrahedral design
which is the basis for the British
"Ambisonic" multi-channel system?
(IMF Products, G.B., Westbourne St,
High Wycombe, Bucks, England.)
ELECTRONICS Australia, December, 1976
words, the two channels should interact
to produce a multiplicity of virtual sound
sources, one for each point source in the
performing group, one for each pipe in
a grand organ, and so on.
Superficially, therefore, I agree with
R.P's statement that there must be "two
effective channels right through the chain
for all sounds". It's a basic requirement
for any 2-channel stereo system. But I
didn't go along with the way he inter¬
preted the statement!
He spoke derisively about "two-
channel mono", as if the term itself car¬
ried its own condemnation; in fact, any
ordinary stereo system relies ultimately
on two channels, both of them mono!
He criticised, by inference, "an impres¬
sion of lateral dispersion", which is
precisely what any 2-channel stereo sys¬
tem gives: not multiple sound sources,
but an impression of multiple sound
sources!
In short, I feel that R.P. tended to justify
a perfectly legitimate point of view on
questionable grounds. If he had said "I
prefer an occasion-orientated, or per¬
formance-orientated recording, made
with a pair of microphones substituting
for the listener's ears", there could have
been little ground for argument. It would
be a value judgment shared by a very
large number of people— and particularly
those interested in classical music.
But when he tried to make capital out
of distinctions between stereo and 2 two-
channel mono, between stereo and
impressions of lateral spread, and the
rewarding or wasteful use of two chan¬
nels, he was providing would-be oppo¬
nents with ready-made ammunition.
F.S. asks whether I personally have put
these theories to the test, presumably
with the objective of arriving at an unam¬
biguous yes-no kind of answer.
No I haven't, and I wouldn't expect to
find such an answer anyway.
The whole thrust of the September dis¬
cussion was towards the conclusion that
the way you go about making a recording
depends on partly what you are trying to
achieve, and partly also on the facilities \
you can organise for the purpose.
And so we come a to a follow-up letter
from the man who started it all; or should
we say re-started it all:
Dear Mr. Williams,
Thank you for your interesting reply to
my letter on the subject of stereo sound.
It wound appear that I have stimulated
a very sensitive nerve.
Firstly, if you care to re-read my letter,
at no time did I specify the form of
transducer to be used to recover the
electronically recorded sound; only that
the said recording be of such a nature
that, given the requisite condition, a pure
stereo signal would be available.
The fact that, at the present time, it is
not possible to reproduce it fully in the
home environment is rather irrelevant.
Since the earliest days of sound broad¬
casting, the vast majority of radio stations
have maintained a quality of transmission
far exceeding that of any known method
of reproduction at the same period of
time by several orders of magnitude. This
has, in no way, deterred them from pur¬
suing this policy.
For exactly the same reasons, I consi¬
der it to be wrong not to provide a
genuine stereo signal on any recording.
Synthetic stereo may be desirable com¬
mercially but doubtful technically.
We know it is physically impossible to
have a full orchestra in the lounge room
and mentally dismiss this, but why must
we add yet another paradox: something
we cannot hear in real life?
With improvements in speaker tech¬
nology we are getting closer to the goal
of a really low distortion system. If really
low overall distortion eventuates, some
of today's artistic performances may be
compromised for posterity, as were
those of earlier times, due to the physical
limitations in recording.
You will note that I have not con¬
sidered the degree of hirsuteness, nor
can I question the undesirability of a
plank suspended above the conductor
supporting an assortment of posteriors.
The relevant merits of different styles
of music were also not raised by me, so
it would be impossible to classify me on
this point, unless we are in agreement
that nothing anyone can do will make the
present pop sound any worse than it
already is!
I thank you for your kind description
of me as a hard liner. At least you have
placed me on the fringe of many distin¬
guished pioneers of hifi , all trying to
improve the quality of sound reproduc¬
tion. After 44 years of professional invol¬
vement in sound reproduction, I still
believe the right way is still the best way,
providing it complies with technical
requirements.
R.P. (Parkdale, Vic)
First let me assure R.P. that, if any sensi¬
tive nerve was affected, it wasn't mine.
I hold no special brief for the multi-mic
technique or any of the other matters
raised in the September issue. As I
pointed out in the particular issue, the
letter epitomised arguments that have
been going on for a very long time and
I sought to react to the letter, not in isola¬
tion, but in the context of all those
decades of discussion.
Nothing that R.P. says in. this second
letter alters his position as a spokesman
for a particular— and legitimate— point of
view. What he is at pains to stress is that
he wants to rise above lesser things and
to uphold the principle of making all
stereo recordings in the "right" way, for
the sake of future generations.
As a grand principle, it sounds very
impressive but I really wonder whether
R.P's "true stereo" has the intrinsic tech¬
nical merit to live up to it.
As a system, it can capture only a limi¬
ted frontal, lateral spread; it cannot
define elevation nor can it isolate and
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Radial droop for 50 ohm
match Accepts 1 1 4 inch
tubing and PL 259 con¬
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Frequency Range 27
MHz Impedance 50
ohms VSWR Less than
T51 Weight 45lbs Wave
14
$49.95
P&P $5.00
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Base Station dual Voltage 240 V AC or 1 2 V. DC.
Fully equipped with 23 American C.B. Channels
Input to final: A M. 8 Watts min. S.S.B. 25 Watts P.E.P.
Dual conversion: 7 I.F.Tsand 6 I F. stages
Noise Blanker: Delta tune (Clarifier) +— 300 Hz.
Meter for, Signal in, R.F. out. S.W.R.
Sensitivity: .5 uv @ 6db Size: 33 x 13.5 x 24.5 cm.
Wt. 7% kg For use with Novice License.
$249^15
THE TRANSCEIVERS ADVERTISED HERE ARE BUILT TO AMERI¬
CAN F.C.C. SPECIFICATIONS. A NOVICE OR HAM LICENCE IS
REQUIRED TO OPERATE SUCH EQUIPMENT IN THIS COUN¬
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See our comprehensive range of CB test equipment & aerials, SWR
meters from $ 1 7. Power meters etc.
All mail enquiries must be accompanied by a self addressed,
stamped envelope.
PETER SHALLEY
“CB SPECIALISTS-^
554 Pacific Hwy Killara
NSW 2071 Tel-4982611
ffcuu$el°cR"> *'R'Ai
If you buy any of the above Transceivers you will be
eligible to buy one Guttergrip or Roof Mount Aerial—
usually $19.50— For only $9.50. Offer lasts till 30th
Dec. 1 976 only.
519-50 p+p 52
68
ELECTRONICS Australia, December, 1976
Dear Sir ,
I would like to add my thoughts to
your article in the September issue of F.A.
From my teenage days in the late
1920 's, I have been dabbling with "fi"
from very low to reasonably "hi and this
is how I see the scene:
To get the true atmosphere of any per¬
formance, whether orchestral , vocal or
whatever , the recording must be made
in proper 4-channel stereo-not the gim¬
micky 4-channel stuff.
The right "atmosphere" can only be
obtained by a correctly balanced 2-
channel performance , with centre phan¬
tom channel , in the front , and with
genuine ambience effects coming from
two rear channels.
If the original performance was before
a "live" audience , so much the better ,
because you would get the sensation of
actually being there.
The only true 4-channel stereo record¬
ing I have heard , which includes all the
ambience sound , is one I made myself
featuring Australia's leading military band.
Two good quality studio mics were
hung over the band on stage to give left
and right frontal sound , the inputs being
carefully balanced to give a centre phan¬
tom channel. Two "ambience" mics
were suspended over the audience , two-
thirds of the way to the rear of the hall
and 10ft out from the walls.
The ambience mics not only captured
the sounds of the band from the walls
and rear of the hall but also the audience
noise like a baby crying and somebody
coughing. And when the audience clap¬
ped after each item , it was all around
you-just like being there. Maybe not
everyone wants to hear babies crying
and people coughing , but it goes to show
that atmosphere can really be captured.
Fortunately , / have room to reproduce
this sound realistically , with a private
theatre in my home , 50ft long and 22ft
wide. The 4-channel tape , as well as
other 4-channel discrete sources , is fed
into two high-power amplifiers feeding
8 speakers: 2 in front , 2 at the rear , and
2 along each wall. When played through
this system , the band recording is the
nearest thing to reality I have yet heard.
It amazes me that , with the advanced
technology at our disposal , we haven't
had much advance in program sources
since the original stereo in the 1950's. I
would like to hear a professionally
recorded 4-channel stereo featuring pro¬
per frontal sound with proper rear
ambience. Why don't the record com¬
panies get on with true 4-channel stereo
tapes? Look at it this way:
Would anyone sooner see a film with
just ordinary frontal sound , or a 70mm
print featuring 6-track stereo-front
speakers and others along each side of
the theatre? You are really part of the
action. Surely this is what sound is all
about. -
Please carry on with the good work.
I. D. (Latrobe, Tas.)
define ambience information. There is no
reason to believe that future technology
will be able to recapture non-existent
spatial information from present-day
stereo, any more than we can capture
non-existent directional information
from old-time mono.
If we are going to strive for a ''right"
way, it should surely be one which seeks
to record at least some of these added
qualities, which is why I added the lines
at the end of the September article
and quite so disdainful of those who are
trying to capture and recreate more
genuine around-the-listener ambience,
with the aid of discrete 4-channel".
Disdainful?
Yes, I used the word quite deliberately,
although not with any intention of involv¬
ing R.P.
But the fact is that many music lovers
have become completely conditioned to
front-only sound, by decades of listening
to ordinary mono and stereo systems.
When recording interests try to capture
or reconstitute the ambience of an audi¬
torium, they are accused of "gim¬
mickry".
To be sure, quadraphonic recording
and reproduction has contained a large
element of gimmickry and artificiality but
part of the struggle is towards reality, not
away from it.
But you just try to convince many
dyed-in-the-wool record buyers of that!
Which leads me to the point that work
being done in England with the so-called
Ambisonic system, and a 4-channel
Blumlein-style microphone cluster could
be heading towards the kind of right
basic system that R.P. has in mind. The
only trouble is that the idea Seems to be
spending an inordinately long period in
the "boffin" stage.
And that leaves just one thing to do:
to read the letter in the panel from j.D.
Obviously a hifi fan from way back, he
manages, quite spontaneously, to come
up with a recipe that variously draws
upon and conflicts with, many of the
foregoing sentiments:
4-channel stereo-not the synthetic
kjnd_genuine frontal sound with phan¬
tom centre channel— dispersed, not clus
ter, microphones— audience noise, even
to crying and coughing. Vet he admits
that many would not want that kind of
distraction, he rejects the kind of 4-
channel material that companies have
found it practical to release, and he longs
for the kind of open-reel tape that the
buying public has virtually rejected.
Is it any wonder that hifi enthusiasts
never run out of the will to argue, or the
raw material to keep them going! ®
trostatic loudspeaker
produced commercially
and is still the standard by which ail otners
are judged. Using closely coupled moving
elements some two hundred times lighter
than the diaphragms of moving coil loud¬
speakers and being entirely free of cabinet
resonances and colouration, this loud-
speaker overcomes the usual major prob¬
lems of loudspeaker design and provides
remarkably natural reproduction of sound.
This explains why the QUAD electrostatic
loudspeaker is used by broadcasting and
recording organisations all over the world,
in applications where quality is of prime
importance, and as a standard of refer¬
ence by the majority of loudspeaker
manufacturers.
QUAD for the closest approach to
the original sound.
QUAD
For details of your nearest dealer
write to British Merchandising Pty
Ltd. 49 51 York St. Sydney 2000. Or
telephone 29-1571.
BK3
A direct conversion
receiver for 3.5MHz
Following on from our recent articles describing transmitting gear
mainly intended for the new amateur Novices, we now present a simple
receiver for the 3.5MHz band. It uses the "direct conversion” principle,
and is in fact the first such receiver we have described. It offers qood
reception of CW and SSB signals using simple circuitry.
by IAN POGSON
Direct conversion receivers have been
described in overseas magazines for the
past ten years or so, and possibly longer,
but we have not entered the field until
now. Like most things, there are argu¬
ments both for and against.
One of the very favourable points
about direct conversion is its relative
simplicity. On the other hand, while they
are quite good for CW and SSB recep¬
tion, they are not the best for AM recep¬
tion. Also, as all or nearly all of the gain
is at audio frequencies, problems of hum
and instability have to be overcome.
However these problems are not
insurmountable and direct conversion
receivers can give quite a good account
of themselves despite the performance
limitations.
Before we go any further, I imagine
that there are many readers who have not
heard of the direct conversion principle.
Basically, the wanted signal is first
selected by one or more tuned circuits,
and may or may not be amplified with
an RF amplifier. The signal is then fed into
a mixer, together with a local oscillator
signal. But in contrast with an ordinary
superhet, where the oscillator frequency
is offset by the value of the intermediate
frequency, here the oscillator is on the
same frequency as the signal. This gives
a direct audio beat instead of an IF.
Let us take the concept a little further.
Suppose that we wish to receive a CW
signal. Any input tuned circuits will be
tuned to the frequency of the wanted sig¬
nal and the local oscillator will also be
tuned to the frequency of the signal. If
the local oscillator is set exactly to the
same frequency as the carrier, we will
have a "zero beat" condition, with no
audio output from the mixer.
Suppose now that we offset the local
oscillator (either high or low) from the
frequency of the wanted signal by 1kHz.
We will now get a beat frequency of
1kHz as output from the mixer. This out¬
put will be at low level and must be
amplified in an audio amplifier system to
drive a pair of headphones or a
loudspeaker.
Again, suppose that we wish to receive
a single sideband signal. This time, we
must adjust the local oscillator frequency
as closely as possible to the suppressed
carrier frequency of the wanted signal.
The sidebands received will now beat
with the local oscillator and the mixer
* output will be the recovered audio of the
signal. This needs to be amplified, as
explained before.
Let us take the explanation a little
further and consider the possibility of
receiving AM signals. Under these condi¬
tions, we must set the local oscillator to
precisely the same frequency as the car¬
rier of the incoming signal. This done, we
are able to resolve the AM signal quite
well. Unfortunately, it is very difficult to
meet this stringent requirement. With the
local oscillator offset from the incoming
carrier, we get a beat frequency equal to
the difference between the two. Also,
beats against the sidebands are confused
and the result is somewhat of a mess.
1 have ac*ded the last paragraph on the
possibility of AM reception so that there
is not likely to be any disappointment
with the performance of this type of
receiver. While capable of resolving CW
and SSB signals quite well, direct-
conversion receivers are not as good for
AM reception.
A look at the circuit will show better
how the foregoing has been achieved.
From the aerial, the signal is fed into a
tuned circuit, consisting of a coil with
three windings, one of which is tuned by
two variable capacitance diodes, back-
to-back. Signals from the tuned circuit
are fed into a double-balanced ring
mixer.
The mixer consists of two transformers
wound on TV "balun" cores, with four
hot-carrier diodes. Output from the
mixer is from the two transformer centre
taps. Injection from the local oscillator is
into the second of the two transfor¬
mers.
The local oscillator is a Hartley, with
a junction FET as the active device. The
tapped coil is tuned with a pair of vari¬
able capacitance diodes, as for the input
circuit. A silicon diode between the FET
ELECTRONICS Australia, December, 1976
Front panel controls are (left to right) mains on/ off, tuning and volume.
gate and ground is to restrict the ampli¬
tude of oscillation.
The tuned circuits are tuned by chang¬
ing the amount of reverse voltage
applied to the variable capacitance
diodes. This is achieved by a potentio¬
meter across the regulated 12V supply,
the voltage from which is fed to each set
of diodes via an RF filter consisting of two
RF chokes and a 0.1 uF capacitor. The
4.7k resistor on the tuning potentiometer
is to assist in reducing cramping at the
low frequency end of the dial.
Output from the mixer passes through
a low pass R-C filter. The bandwidth of
this filter actually determines the selec¬
tivity of the system. Consistent with
simplicity, the filter constants give a fair
degree of selectivity. The selectivity
could be narrowed by making a more
complex filter but this was considered
not to be necessary.
The low level signal from the low pass
filter is amplified in a single stage audio
preamplifier. A volume control follows,
the output of which is fed into a small
1C audio amplifier, capable of driving a
loudspeaker.
The power supply is a dual arran¬
gement, from a small power transformer
with a 12.6V CT secondary winding. Four
silicon diodes are connected in a bridge
across the transformer secondary. The
bridge output gives about 18V DC, which
is regulated down to 12V with a resistor
and zener diode. Approximately 9V DC
is obtained from the transformer centre
tap to supply the main audio amplifier.
Before leaving the circuit, you may be
wondering why I have not mentioned the
220pF capacitor and the parallel trap cir¬
cuit between the aerial terminal and the
first tuned circuit. The Q of the first tuned
circuit is rather low and this lead to a
couple of problems. The second har¬
monic of the oscillator could beat with
strong unwanted signals which, although
attenuated, came through along with the
wanted signals. Of course, the signals
were also at twice the frequency of the
tuning. As an example, VNG on 7.5MHz
could be tuned in at 3.75MHz on the dial.
COIL WINDING DATA
Trap:
50 turns 30B&S enamel close wound
on Neosid 7.6mm x 32mm former with
grade 900 slug.
Aerial coil :
700 turns 30B&S enamel close wound
on Neosid 7.6mm x 58mm former with
grade 900 slug. Output winding: 20
turns 30B&S enamel close wound
over earthy end of tuned winding.
Aerial winding: 10 turns 30B&S
enamel close wound over output
winding.
Oscillator coil:
100 turns , tapped 20 turns from earthy
end , 30B&S enamel close wound on
Neosid 7.6mm x 58mm former with
grade 900 slug.
Mixer transformers:
Take three lengths 30B&S enamel wire
and twist together to a pitch of about
6mm. Wind 15 turns and terminate as
shown in diagram. _
Australia, December, 1976 71
E.D.&E. (SALES) PTY. LTD
EDUC-8 COMPUTER-COMPLETE KIT
(OCT-Nov-DEC 1974) $402.40 (Plus Tax)
OR INDIVIDUAL COMPONENTS
AS REQUIRED
MAJOR STOCKISTS OF ALL GENERAL RADIO & ELECTRONIC COMPONENT PARTS - YOU
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AUDIO
1 Direct Reading A F Gen
2 SQ Wave Gen-1 OHz-1 MHz
3 Solid State A F Gen
4 Additive Freq Meter
5 A F Tone Burst Gen
6 Laboratory Solid State A F
Gen
7 Scaler/ Divider Unit
8 Crystal Freq Calibrator
9 Direct Reading AF Meter-
(0-200KH* - 1 0MV-2V)
10 High Performance A F Gen
1 1 White Noise Gen
12 -
13 -
14 -
AUTOMOTIVE UNITS
1 5 Tacho & Dwell Angle for Ser¬
vice Stations
1 6 Dwell Extender Unit
1 7 Solid State - CDI
18 All Electronic Ignition System
1 9 Windscreen Van-Wiper
20 Tacho & Dwell Unit
21 Brake Light Warning
22 Emergency Flasher
23 High Efficiency Flasher
24 Solid State Volt Reg
25 Car Theft Alarm System
26 Ignition Analyser & Tach¬
ometer Unit
2 7 Strobe Adaptor for Ignition
Analyser
28 Car Burglar Alarm
29 1975. C.D.I Unit
BATTERY CHARGERS
30 6 Volt — 1 Amp
31 12 Volt - 1 Amp
32 Automatic H/Duty
33 1-14 Volt - 4 Amp
34 1 973 Automatic Unit
35 Constant Current Unit
36 -
37 -
CONVERTERS - INVERTERS
38 12 VDC 300/ 600V 100W
39 12 VDC 240 VAC 20W
40 1 2 VDC 240 VAC 50W
41 24 VDC 300 VDC 1 40W
42 24 VDC 800 VDC 160W
43 -
44 -
C.R.O. UNITS
45 1 963 3" Calibrated
46 1966 3" C.R 0
47 1968 3” Audio C R O
48 C.R.O Electronic Switch
49 C.R 0 Wideband P/Amp
50 C.R.O. Calibrator
51 -
52 -
INTRUDER WARNING SYSTEM
53 Electronic Thief Trap
54 Infrared Alarm System
55 Simple Burglar Alarm
56 Light Beam Relay
57 Car Burglar Alarm
MULTIMETERS & V O M
58 Protected D C Multimeter.
59 Meterless Voltmeter
60 Wide Range Voltmeter
61 F E T. D C.
62 1966 V TV M
63 1968 Solid State V.O M
64 1973 Digital V O. M (1)
65 1973 Digital V O.M. (2)
66 High Linearity A C. Millivolt-
meter
67 -
PHOTOGRAPHIC UNITS
69 50 Day Delay Timer
70 Regulated Enlarger Line.
71 Slave Flash Unit
72 Sound Triggered Flash
73 Solid State Timer
74 Auto Trigger For Time Lapse
Movies
75 -
76 -
REGULATED POWER SUPPLIES
77 Laboratory Type 30/1 Unit.
78 Laboratory Type Dual Power
Supply
79 Serviceman s Power Supply
80 Solid State H V Unit
81 1C Variable Supply Unit.
82 1972IC Unit (E/T)
83 Simple 5V 1A Unit
84 Simple 3-6 V 3 5A Unit
85 S/C Proof 0 30 VDC at 1A
86 Reg 0-30VDC at 3A O/L
Protected
87 Variable Reg 1 2V-05A.
88 Reg 0/ Load &S/C Protection
60 VDC at 2A (1973) - EA
89 -
90 -
R.F. INSTRUMENTS
91 Solid State Test Osc.
92 Signal Injector & R/C Bridge
93 Solid State Dip Osc
94 Q' Meter
95 Laser Unit.
96 Digital Freq Meter 200KHz
97 Digital Freq Meter 70MHz
98 IF Alignment Osc
99 2 7MHz Field Strength Meter
100 lOOKHz Crystal Cal
101 1MHz Crystal Cal
102 Solid State Dip Osc
103 VH.F. Dip Osc.
104 V.H F Powermatch.
105 V.H F F/S Detector
106 S W R Reflectometer r f
107 R F Impedance Bridge-
108 Signal Injector
109 1972 FET Dipper
110 Digital Freq Meter
1 1 1 Simple Logic Probe
112 Frequency Counter & DVM
Adaptor
1 1 3 Improved Logic Probe
114 Digital Logic Trainer
1 15 Digital Scaler/Preamp
1 16 Digital Pulser Probe
1 1 7 Antenna Noise Bridge
118 Solid State Signal Tracer
1 19 1973 Signal Injector
120 Silicon Diode Sweep Gen.
TRAIN CONTROL UNITS
124 Model Control 1967
125 Model Control with Simulated
Inertia.
126 Hi-Power unit 1968
127 Power Supply Unit
128 SCR-PUT Unit 1971.
1 29 SCR-PUT Unit with Simulated
Inertia 1971.
130 Electronic Steam Whistle
131 Electronic Chuffer
TV INSTRUMENTS
1 34 Silicon Diode Sweep Gen
135 Silicon Diode Noise Gen
136 Transistor Pattern Gen.
137 TV Synch & Pattern Gen
1 38 Cross Hatch & Bar-Gen
VOLTAGE CURRENT CONTROL
UNITS
142 Auto Light Control
143 Bright/Dim Unit 1971
144 S C R Speed Controller
145 Fluorescent Light Dimmer
146 Autodim-Triac 6 Amp
147 Van-Light 1973
148 Stage etc Autodimmer 2KW
149 Auto Dimmer 4 & 6KW
RECEIVERS — TRANSMITTERS —
CONVERTERS
153 3 Band 2 Valve
154 3 Band 3 Valve
155 1967 All Wave 2.
156 1967 All Wave 3
157 1967 All Wave 4
158 1967 All Wave 5.
159 1967 All Wave 6
160 1967 All Wave 7.
161 Solid State FET 3 B/C
162 Solid State FET 3 S/W
163 240 Communications RX.
164 27 MHz Radio Control RX
165 All Wave IC2
166 Fremodyne 4-1970
167 Fremodyne 4-1 970.
R F Section Only.
168 110 Communications RX.
169 160 Communications RX.
1 70 3 Band Preselector
171 Radio Control Line RX
172 Deltahet MK2 Solid State
Communications RX
173 Interstate 1 Transistor Re¬
ceiver
174 Crystal Locked H F. RX
175 E/A 1 30 Receiver
176 E.A 1 38 Tu nor /Receiver
177 Ferranti 1C Receiver
178 Ferranti 1C Rec/Amp
179 7 Transistor Rec
180 -
181 -
TRANSMITTERS
182 52MHz AM
183 52MHz Handset
184 144MHz Handset
CONVERTERS
187 MOSFET 52MHz
188 2-6MHz
189 6-19 MHz
190 V.H F
191 Crystal Locked HF & VHF
AMPLIFIERS PREAMPS & CON¬
TROL UNITS MONAURAL
194 Mullard 3-3.
195 Modular 5-10 & 25 Watt
STEREO
196 1972 PM 129 3 Watt
197 Philips Twin 10-10W.
198 PM 10 + 10W
199 PM 128-1970
200 PM 132-1971.
201 ETI-425 Amp & Preamp
202 ETI-425 Complete System
203 ETI-41 6 Amp
204 PM 136 Amp 1972
205 PM 137 Amp 1973
205A PM 143
GUITAR UNITS
209 P/M 125 50W
210 E/T 100 100W
21 1 P/M 134 21W
212 P/M 138 20W
213 Modular 200W
214 Reverb Unit.
215 Waa-Waa Unit
216 Fuzz Box.
217 Sustain Unit
PUBLIC ADDRESS UNITS
219 Loud Hailer Unit.
220 P A. Amp & Mixer
221 P/M 135 12W
222 Modular 25W
223 Modular 50W
CONTROL UNITS
225 P/M 112
226 P/M 120
227 P/M 127
MIXER UNITS
229 FET 4 Channel
230 ETI Master Mixer
231 Simple 3 Channel
%
TUNER UNITS
232 P/M 122
233 P/M 123
234 P/M 138
235 Simple B/C
236 PM 146 AM-FM
PREAMPLIFIERS
237 Silicon Mono
238 Silicon Stereo
239 FET Mono >
240 Dynamic Mic Mono
241 Dynamic Mic Stereo
242 P/M 115 Stereo
243 -
MISCELLANEOUS KITS
244 Geiger Counter
245 Direct Reading Impedance
Meter
246 -
247 Electronic Anemometer
248 Simple Proximity Alarm
249 Pipe & Wiring Locator
250 Resonance Meter
251 Electric Fence
252 Metronome Ace Beat
253 Tiansistor Test Set
254 Electronic Thermometer.
255 Flasher Unit
256 Lie Detector
257 Metal Locator
258 Stroboscope Unit
259 Electronic Canary
260 240 V Lamp Flasher
261 Electronic Siren
262 Probe Capacitance Meter
263 Moisture Alarm
264 AC Line Filter
265 Proximity Switch
266 Silicon Probe Electronic Ther¬
mometer
267 Transistor/ FET Tester
268 Touch Alarm
269 Intercom Unit
270 Light Operated Switch
271 Audio /Visual Metronome
272 Capacitance Leakage
273 Audio Continuity Checker
274 Bongo Drums
275 Simple Metal Locator
276 Keyless Organ.
277 Musicolour
278 Stereo H/ Phone Adaptor
279 Attack Decay Unit
280 Tape Recorder Vox Relay
281 Tape Slide Synchroniser
282 Tape Actuated Relay
283 Auto Drums
284 1C Vol Compressor
285 Audio Attenuator
286 Thermocouple Meter
287 Door Monitor
288 Earth ' R” Meter
289 Shorted Turns Tester
290 Zenor Diode Tester
291 Morse Code Osc
292 Simple Electronic Organ
293 Pollution & Gas Analyser
294 Universal H/ Phone Adaptor
295 Super Stereo ETI- 4 10
296 "Q" Multiplier
297 Optomin
PHONE
662-3506
En a. p (SALES)
m Urn GL C. PTY. LTD.
1 18 LONSDALE STREET, MELBOURNE —3000 — VIC.
PHONE
662-3506
72
ELECTRONICS Australia, December 1976
1
3.5MHz Direct Conversion Receiver
The trap was added, tuned to 7.5MHz,
and this problem was solved.
If you happen to live to close to one
or more broadcast transmitters, then
there may also be trouble with them
breaking through. The 220pF capacitor
cures this one.
The problems just mentioned have
arisen because the design has been
simplified by as much as could be con¬
sidered practical. Some improvements
could be effected by introducing an FET
source-follower between the tuned cir¬
cuit and the input winding of the transfor¬
mer for the mixer. The low impedance
aerial coil winding presently feeding into
the mixer would be omitted and the
tuned winding itself would be connected
to the source-follower, via a blocking
capacitor.
By making the above modification,
there should be some increase in gain.
Also, the Q of the tuned circuit should
be improved. However, this is not neces¬
sary and the unit as it stands is capable
of quite a good performance.
Every effort has been made to be sure
that the components used are readily
available on the Australian market.
However, to make it somewhat easier for
the intending builder, a few comments
on some of the components may be
helpful.
Resistors, capacitors and transistors
should present no problems. We under¬
stand that there are also ample stocks of
the TAA300 audio 1C. Diodes for the
power supply may be any brand equiva¬
lent to the type specified. The variable
capacitance diodes are very important
though, and the type BA102 must be
used. .
The hot carrier diodes used in the
mixer are ideal for this application and
should be used for best results.
However, they are rather expensive and
if you wish, the gold bonded germanium
type OA47 may be worth trying. Even the
common OA90 may be satisfactory.
However, in the latter case, it may be
necessary to increase the value of the
lOOpF coupling capacitor between the
oscillator and the mixer.
The two RF chokes are not critical and
any value between about 330uH and
ImH should be satisfactory. Apart from
the coil former for the trap, the other two
formers must be the Neosid type speci¬
fied, as they must fit the printed board.
While different types of formers may be
satisfactory for the mixer transformers,
we suggest that you use those which are
normally intended for use on TV baluns.
The transformer which we used is a
type PF2851 made by Ferguson. This is
a readily available type, rated at 2.5VA.
However, there are other similar types
available which should be quite satisfac¬
tory. These include the newer line now
offered by Ferguson, types PL12/5VA
and PT12/5VA. If you wish to use the lat
ter types then special mounting arrange¬
ments have to be considered, as they are
intended for use on printed boards.
The printed board for the prototype
was supplied by RCS Radio who will be
making boards available, either direct or
This diagram shows the wiring termina¬
tions for the two mixer transformers.
through your usual supplier. Alterna¬
tively, we imagine that other manufactu-
rers will also be making boards
available.
The dial arrangement consists ot a
drive mechanism and a scale. The drive
is the well known planetary type sold
under the label brand and is available
from Watkin Wynne Pty Ltd, 32 Falcon
Street, Crows Nest 2065, or through your
local supplier. The scale is simply a card
calibrated and covered with a piece ot
sheet perspex. More will be said about
the scale when alignment and calibration
are discussed. .
The case which we used was obtained
from Radio Despatch Service, 869
George Street, Sydney, 2000. You may
obtain a similar case from the above
The case is a matter of choice but we
strongly suggest that it be a metal one,
to minimise the effect of body capaci¬
tance. .. , .
Construction of this little receiver is
fairly straightforward. A good place to
start is with the coils. These should be
wound according to the information
given in the table. The aerial and oscilla¬
tor coils should be terminated according
to the numbering given on the circuit, so
that the windings match up with the
_
73
70 BATESFORD ROAD, CHADSTONE,
VICTORIA, 3148, AUSTRALIA
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SERVICES
E&L INSTRUMENTS
GARRARD
HARTLAND Mfg (
J.B.L.
KEF.
L.P.S. RESEARCH
MANN COMPONENTS
PRIMO
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PRODUCTS
• AMPLIERS
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HILLS E.F.C. RANGE 75 ohm
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ELECTRONICS Australia, December, 1976 *
3.5MHz DC Receiver
printed board. Make sure that the oscilla¬
tor coil is firmly wound to ensure a stable
oscillator signal. Pins 4 and 6 should be
bridged.
Winding the mixer transformers can be
a little tricky. Make sure that you have
sufficient length of wire, when twisted,
to wind 15 turns. One turn constitutes a
pass through both holes in the former.
Keep the winding firm, otherwise you
may have trouble getting on the 15 turns.
On the other hand, the number of turns
is not particularly critical and if you have
space left, then you may add extra turns
up to about 20 or so if you wish.
Having done the windings, the ter¬
minations have to be sorted out with a
multimeter and the terminations done
according to the drawing.
Assembly of the printed board is best
done by fixing the small components
first. Resistors and diodes go first,
followed by capacitors, transistors, 1C,
and finally the coils. Make sure that all
diodes, transistors and electrolytic
capacitors are connected with correct
polarity.
Before fixing the aerial and oscillator
coils to the board; bend the can lugs over
so that they interfere with the mounting
screw holes. This ensures that when you
screw the coil to, the board, the can will
be effectively earthed. Fixing the mixer
transformers may be effected by using
small pieces of double-sided adhesive
tape, or simply by using a suitable glue,
such as Tarzan's Grip.
When soldering components to the
board, always have a good, clean, hot
iron. Use a good quality resin cored sol¬
der and avoid overheating components.
But at the same time, avoid "dry" joints.
Apart from the external leads to and
from the board, there are two "jumpers"
required. One is from the centre tap of
the mixer input transformer. Run a piece
of hookup wire from the copper pad
under the board to the emitter connec¬
tion of the BC549 preamplifier transistor.
Another lead must also be run from the
PARTS LIST
7 Metal case, 230mm wide x 90mm
\ high x 210mm deep
1 label planetary dial drive, with
pointer
: 2 Knobs
7 Switch , SPDT
I 7 Printed board, 78mm x 184mm,
code 76R12
‘ 7 Power transformer, 240V primary,
12.6V CT secondary, 2.5V A
1 Terminal strip, 3-position
: 1 Speaker socket, 2-pin
• 1 Coax socket
2 Terminals, 1 red, 1 black
4 Spacers, brass, Vzin long , tapped /sin
Whitworth
4 Silicon diodes, EM401 or similar
4 Variable capacitance diodes,
BA102
4 Hot-carrier diodes, 5082/2811 (see
text) .
7 Silicon diode, 1N914A or similar
1 Zener diode, BZX79 C12
1 Transistor , 2N5485 or similar
1 Transistor, BC549, BC209, BC109
1 1C, TAA300 , with flag heat sink
2 RF chokes, 820uH
1 Coil former, Neosid 7.6mm x 32mm
with grade 900 slug
2 Coil formers, Neosid 7.6mm x
58mm with can and grade 900 slug
RESISTORS (ViW unless stated other-
wise)
1 47 ohms
1 6 80 ohms
2 Ik
2 2.2k
2 4.7k
1 25k trimpot
1 33k
1 47k
1 100k log pot
1 100k linear pot
1 390k
1 3.3M
CAPACITORS
1 39pF NPO ceramic
1 47pF polystyrene
2 6-60pF Philips trimmer
1 lOOpF polystyrene
1 220pF polystyrene
2 .01 uF 100V greencap
1 0.22uF 100V greencap
1 .047uF 25V ceramic
4 O.luF 100V greencap
1 0.47uF 35VW tantalum
1 22uF 16VW electrolytic
1 25uF 6.4VW electrolytic
1 125uF 10VW electrolytic
1 200uF 10VW electrolytic
1 320uF 6.4VW electrolytic
1 IOOOuF 25V W electrolytic
1 2200uF 16VW electrolytic
SUNDRIES
Hookup wire, solder, solder lugs, rub¬
ber grommet, 3-core flex, 3-pin plug,
cable clamp, screws, nuts.
Note: Resistor wattage ratings and
capacitor voltage ratings are those
used on the prototype. Components
with higher ratings may generally be
used, providing they are physically
compatible. Components with lower
ratings may also be used in some
cases if available, providing ratings are
not exceeded.
ELECTRONICS Australia, December, 1976
75
3.5MHz DC Receiver
+ 9V point from the power supply, to the
corresponding point at the audio
amplifier output. Or, it may be run to the
speaker socket terminal.
Fitting components to the case is sim¬
ple enough and the location of the items
may be seen in the photographs.
However, two points are worth mention¬
ing. It is most important that you use
metal spacers to fix the printed board to
the case. If this is not done there is likely
to be a hum problem. Also, when fixing
the tuning potentiometer to the dial
drive, we used some long screws and a
small metal plate to which the poten¬
tiometer is fixed. The spindle is cut to
length and mounting is adjusted so that
the potentiometer rotates smoothly.
Although the audio 1C is likely to be
run at well below its full output
capability, it would be wise to fit a heat
sink to the 1C. You can either buy one
or alternatively, fashion one out of a
piece of scrap aluminium. We made one
from a piece measuring 50mm x 12mm.
One end was wound around a 5/16in
diameter drill and the resulting loop was
adjusted by hand so that it was a neat
fit over the case of the 1C.
With all the items fixed to the case, all
interconnecting wiring can be done.
After terminating the mains lead in the
terminal strip, we ran the neutral lead
direct to the transformer and the active
via the switch on the front panel. The
mains earth was taken to a lug under the
coax aerial socket mounting screw. We
ran a lead from the earth copper at the
back of the board, to the same earth lug.
The coax socket is connected to the
other aerial terminal and the 220pF
capacitor is swung across to the trap
coil.
resistor is also connected directly to the
tuning potentiometer.
Before making the adjustments, a
careful check should be made to ensure
that all components are in the right
places and that there have been no errors
or omissions.
Satisfied that all is well, turn the volume
control right off and set the trimpot on
the audio amplifier to mid position. Lift
the lead from the + 9V supply point and
insert a multimeter with it set to the 10mA
range or higher. Switch on, and adjust the
trimpot for a reading of 8mA. Then
switch off and resolder the lead.
Although we have not mentioned it so
far, a dial scale is needed and we have
reproduced a full size copy of the one
which was used on the prototype. Due
to the variations associated with varicap
diode tuning, more than likely your dial
calibrations will not be the same as those
of the prototype. However, the re¬
produced scale can be useful as a guide
as to what to expect. Just how you settle
on your dial scale will be up to each
individual to decide.
Whatever you may decide, two points
on your scale will correspond with those
on the prototype. They are the 3.5MHz
and the 4.0MHz points and these should
be marked before calibration and align¬
ment is done.
We will assume that you have access
to a signal generator or some other
means of identifying frequencies within
‘ to facilitate
76 ELECTRONICS Australia, December, 1976
the range of interest. Set the generator
to 3.5MHz and set the receiver dial to the
same point on the dial. Switch on and
adjust the slug in the oscillator coil until
a signal is heard. Now adjust the slug in
the aerial coil for maximum response.
Now set both the receiver and genera¬
tor for 4MHz. Adjust the oscillator trim¬
mer until a signal is heard. Then adjust
the trimmer on the aerial coil for
maximum response. In common with all
alignment procedures of this nature, it is
now necessary to go back and forth from
one end of the scale to the other, each
time making a smaller adjustment to the
appropriate slug or trimmer until both
end points are accurately set. Alignment
is then complete.
Although alignment is finished, we still
have to do something about calibration.
If you have a copy of the original in place,
then by means of the generator or some
other source of known marker frequen¬
cies, check each of the points along the
scale. If you are lucky they may be close
enough, and you may elect to use the
copy of the original scale. On the other
hand, you may decide to set your own
calibration points.
You will have noticed that the scale
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A view of the rear panel. The speaker
socket is at left , with the aerial socket and
terminals to the right.
calibrations are not linear. This is due to
the characteristics of the tuning diodes
and other constants relating to them in
the tuning system, * and is difficult to
avoid, short of taking rather elaborate
steps.
With your direct conversion receiver
now operational, you will/ieed a good
aerial system for best results. Preferably,
the aerial should be one cut for the
3.5MHz band, with a properly matched
coax feeder. Given this, the little receiver
should give a good account of itself on
signals from amateurs, etc, operating on
CW and SSB, within the tuning range.
If you find that you are having trouble
with signals transmitting in the range
between 7MHz and 8MHz breaking
through and being tuned along with the
wanted signals, then the trap in the aerial
circuit needs adjustment. As an example
you may be receiving the standard time
and frequency station VNG, actually on
7.5MHz, on 3.75MHz on your dial. If this
is the case, tune in the unwanted signal
and adjust the slug in the trap for
minimum response. By adjusting the trap
here in the middle of the band, it should
be effective right across the tuning
range. w
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ELECTRONICS Australia, December, 1976 77
The Serviceman
- ac— =
Handyman successes— and failures
The do-it-yourself types who attempt their own TV repairs experience
varying degrees of success— ranging all the way from doing a good
job at a considerable cost saving to complete failure, plus unnecessary
expense and, sometimes, adding more damage to the original fault.
With the advent of colour, and a new
colour TV set, a lot of people find them¬
selves with a monochrome receiver on
their hands earmarked as a second set
for the rumpus room or children's den.
’ If, or when, it gives trouble there is a
strong temptation to "have a go" them¬
selves, on the basis that it is no longer
the main set, not worth very much, and
that the cost of a complete overhaul may
well be more than it is worth. So, on the
basis that there is little to lose, they tackle
it themselves.
The average handyman prides himself
on being able to repair just about any¬
thing around the home-from the lawn-
mower to the family car; from the electric
iron cord to the TV set. As readers can
well imagine, this last one is often his
Waterloo.
He usually tackles the TV set by clean¬
ing out the accumulated dust and then
purchasing new valves to replace any
suspect ones. The reasons for suspecting
particular valves are many and varied.
"It doesn't light up as bright as the
others."
"It looks crook."
"It gets too hot."
And so on . . .
A common trap is the EHT rectifier.
"It's got to be that one, 'cos it's the only
one that doesn't light."
There are two traps here. One is the
fact that the design and/or location of
some EHT rectifiers makes it almost
impossible to see the filament. The other
is the fact that this filament is not
supplied from the normal heater line, but
from a loop around the EHT trans¬
former.
As a result, any malfunction which
seriously upsets the operation of the line
output stage will most likely show up as
failure of the EHT rectifier filament. But
try to convince some customers of this.
On more than one occasion I have failed
to get this message across, the customer
insisting on buying a new valve. Later,
when it has failed to cure the trouble, he
comes back, somewhat sheepishly/for
more assistance.
78 ELECTRONICS Australia, December, 19
I was prompted in this brief reminis¬
cence by my most recent do-it-yourself
type. He walked into the shop on a Satur¬
day morning and handed me a piece of
paper with "23FSP4" written on it and
asked, "Have you got one of those?"
He went on to explain that his TV set
had suffered from a very dark picture for
some time, and had now lost the picture
entirely. Since a friend had a similar set,
with similar symptoms, which had been
fixed by fitting a new picture tube, he
reasoned that his could be fixed in the
same way.
Also, he had made a careful study of
how the tube was fitted in the cabinet
and felt quite sure that, if he took care,
he wouldn't have any trouble fitting the
new tube.
It so happened that I did have such a
tube in stock but, before handing it over
I advised him of the dangers associated
with careless handling of a picture tube,
the damage they could cause if they
imploded, and the main precautions to
take in handling them.
Then, the transaction completed, he
loaded the tube into his car and drove
off to an interesting Saturday afternoon's
work fitting it in the cabinet.
I don't suppose I was really surprised
when he turned up on the following
Monday morning, together with the set
and the rather sheepish confession that
it still did not work. Would I have a look
at it and give him a report when he called
back late in the afternoon?
My first step was to check his installa¬
tion of the tube. I was agreeably
surprised to find that he had done
everything correctly; I could not have
done a better job myself.
Next I switched the set on and
checked the EHT, which was exactly
zero. This set uses a 6AL3 damper diode
with a 27 ohm fusible resistor in the plate
circuit, the latter intended to provide
protection in the event of circuit mal¬
functions, particularly any which affects
the line drive to the 6CM5 line output
valve. This resistor was cooked.
Leaving it for the moment I checked
for bias on the grid of the 6CM5. There
was none-a clear indication of Jack of
line drive and, equally, of the failure of
the line oscillator stage.
From previous experience I knew that
the most likely cause of such a failure was
an open circuit horizontal oscillator coil.
Sure enough, a quick check with the
ohmmeter confirmed this.
It needed only a few minutes to
replace the faulty coil and faulty resistor,
after which the set sprang into life. I
aligned the new oscillator coil and gave
all the other controls and adjustments a
routine check.
The set was now working reasonably
well, but I went over the valves and
checked each one in the tester,
experience having taught me that this
model set, at this age, usually had one
or two just about ready to replace.
In this case I found a weak 6X9 in the
IF strip and, when this was replaced, the
old set turned in a virtually new perform¬
ance. It was a very happy customer who
picked up his set late that afternoon; not
only because it was working well, but
also because it had turned out to be such
a simple fault. Also, I suspect, because
of his personal involvement in the job.
And did the old picture tube really
need to be replaced? I have no way of
knowing and I felt it more diplomatic not
to raise the point. Doubtless the cus¬
tomer had asked himself the same ques¬
tion but would prefer not to be reminded
of the possibility that he had bought a
new tube unnecessarily. So, while ever
the question remained unanswered, he
could at least console himself with the
possibility that it was weak.
But I suspect he may hesitate in future
before he makes such a sweeping diag¬
nosis.
Still on the do-it-yourself theme, here
are a couple of letters from readers
whose efforts have been rather more
successful. The first is from a Mr G. P. of
Perth, WA, who, while only an amateur
in matters electronic, was still able to
carry out a worthwhile overhaul on an
old TV set. He writes:
"Carried out a satisfying exercise on
our B&W TV set which is some47 years
old. Received a letter from the main¬
tenance firm saying that they were dis¬
continuing the contract owing the
inability to obtain spare parts.
"When it duly failed, I took a deep
breath, and removed the back panel. The
most impressive feature was the number
of old paper capacitors, many of which
had shed their wax content with the sum¬
mer heat here. Some were covered in
dust which was arranged in a sort of
corona pattern built up around the
capacitor.
"Needless to say, many of the said
capacitors were functioning more as
resistors. Tore the whole board down
and replaced everything with modern
p astic equivalents, plus new valves and
electrolytics.
"With careful alignment the result was
quite startling, as it now pulls in a country
TV station about a hundred miles from
here, doubtless due to some freak recep¬
tion effect."
Well, that's one enthusiast's solution to
the problem of keeping an old TV set
going for a few more years. Whether it
is worthwile depends a good deal on
who does the work. If it is by a profes¬
sional serviceman the labour cost might
well be far more than the set was worth,
particularly if a nasty fault was discovered
half way through the exercise.
But where, as in this case, it can be
done by the owner the only tangible
expense is that for new parts. Not only
does the labour not cost anything, the
person supplying it might actually enjoy
the exercise, and learn something into
the bargain.
And from another reader comes a tip
which is worth remembering. He is Mr
E.R., of Moorabbin, Victoria. He writes:
"An article by you several years ago
referred to faulty valves caused by the
deposit of a metallised film on the mica
separators inside the envelope.
"My aged mantel receiver recently suf¬
fered fluctuating sensitivity in the front
end and a VTVM check of the 6BE6 con¬
verter valve showed the grid to be
slightly positive. A resistance check
revealed some 30M between the grid pin
and the plate and screen pins.
"I pushed a piece of hookup wire over
the grid pin so that the wire was in con¬
tact with it and making sure that the
insulation completely covered it.
Another lead was connected to the plate
and screen pins.
"I connected the plate/screen lead to
a suitable chassis point on my car and the
grid pin to one of the HT leads removed
from a spark plug. Starting the engine d if1
the rest. An ohmmeter check revealed no
readable conductance between the grid
and other pins. More importantly, the set
now behaved normally."
In lighter vein, here is a story which
demonstrates some kind of poetic jus¬
tice. It was related to me by my amateur
friend, who found himself caught up in
a typical TV interference problem, of
which he stood accused.
More specifically, three of his neigh¬
bours confronted him one morning with
the accusation that his amateur transmis¬
sions were causing interference to their
TV sets. One of the three, who seemed
to have adopted the role of spokesman,
was particularly indignant, demanding
that ". . . something be done about it!".
My friend, on the other hand, decided
to play it cool. For one thing, he was
pretty well convinced that he was not to
blame. As he put it to me, "Whenever
anyone experiences interference on
radio or TV, and there is an amateur in
the district, he is sure to cop the blame.
In fact, the amount of interference
caused by amateurs is minimal and, what
is more, is controllable. So I knew that,
one way or another, I could clear
myself."
To them he explained that he is
required, under the terms of his licence,
to keep a log of all transmissions.
Therefore, if they would keep a record
of all cases of interference over, say, the
next week, this could then be compared
with his log and it would be easy to see
which of his transmissions, if any, was the
likely cause.
They agreed to this, though without
much enthusiasm. But they did turn up
the next weekend with a list of inter¬
ference times. When these were* com¬
pared with the log book it was obvious
that none of the times coincided with the
transmissions.
"But", said my friend, "they didn't
believe me. While they didn't say as
much, it was obvious that they thought
I had faked the log book."
On the other hand, there was now no
doubt in his mind that he was not
responsible, so he could afford to be a
bit cocky. "Well," he told them, "since
it is not being caused by my transmis¬
sions, there is little more I can do to help
you. I suggest that you contact the Radio
Branch and ask for their help. They are
well equipped to track down such inter¬
ference, and will be quite willing to
help"
But, for some reason best known to
themselves, they elected not to take his
advice but continued to complain, to
other people, about his transmissions.
The next thing that happened was that
my friend's annual holidays fell due, and
he took off down the coast for several
hundred miles, where he remained for
the next three weeks. And during this
time the interference continued.
By now the group were forced to
admit , rather reluctantly, that ". . . he
probably was not to blame."
And that was the last my friend heard
of the matter, at least directly and for
several months. Then the sequel filtered
back to him via a friend of a friend, etc.
It seemed that, a few weeks after my
friend's holidays, the spokesman's TV set
packed up and was forced to call in a ser¬
viceman. The serviceman quickly found
the trouble - the technical details were
lost in transit - and, as he was fixing it,
he commented, "This fault would have
been causing interference on your pic¬
ture. Not only that, it has probably been
causing interference to all the sets in the
immediate vicinity."
As I said at the beginning, some kind
of poetic justice. And, of course, it also
explains why the group, and the spokes¬
man in particular, suddenly fell silent
after making such a fuss.
As to the nature of the fault, I can only
guess. The most likely explanation is an
EHT fault similar to that which I
described in the May 1976 issue. This was
a dry joint in the top cap of the EHT rec¬
tifier, the resultant arc causing severe
interference in both the set itself, and
also in a neighbouring set. w
LAFAYETTE
27 MHz TWO-WAY RADIO
FOR INDUSTRY, FARM.
BOATS, SPORTS, ETC.
MICRO 66
Only 1-15/ 16"H x 5-3/ 16"Wx 6 13/ 16"D.
5 WATTS
6 CHANNELS
$139.50 (Crystals Extra)
The latest in the famous LAFAYETTE Micro series the
MICRO 66 embodies the versatility, reliability and perfor¬
mance which have made LAFAYETTE famous throughout
the world in 27MHz communications With an extra sensi¬
tive receiver of better than 1 uV for 1 0db S-to-N ratio,
Range-Boost modulation circuitry, a built-in speaker
plus push-button selected external speaker-microphone
(supplied), the MICRO 66 is ideal for Boats or Base Station
operation Operates from 1 2 V DC or 240V AC with
optional Base Station Power Suoply
5 WATTS
12 CHANNELS
DYNA-COM 12A
$139.50 (Crystals Extra)
A powerful 5-Watts input power in
a hand-held transceiver! Excellent
sensitivity and selectivity. Rug¬
gedly designed for extra reliable
performance This high-power
walkie-talkie operates from internal
battferies (rechargeable Ni-cad bat¬
teries available) or an external 12V
source.
icS3
1 WATT 3 CHANNELS
Model HA-310
$73.50 (Incl. 27 240MHz)
1.000 s of LAFAYETTE HA-310
walkie-talkies in use m Australia.
100.000 s throughout the world
attest to their superior qualities A
professionally designed, sturdily
constructed, commercial quality
unit for top performance and long
term reliability Rechargeable
Ni-cad batteries are available to
suit.
All above transceivers are P.M.G.
Type Approved (Licence Required).
A LARGE RANGE OF ACCESSORIES IS AVAIL-
ABLE ANTENNAS. CRYSTALS, CONNECTORS.
ETC PLEASE ENQUIRE FOR DETAILS.
LAFAYETTE
ELECTRONICS
div of Electron Tube Distributors P/L
94 ST. KILDA RD. ST. KILDA
VIC., 3182 Phone 94 6036
ci crTonMirQ Australia December. 1976
1
WANT TO RECEIVE A
)f CHRISTMAS PRESENT
* YOU WANT? FOLLOW
T the instructions \^y
^ AT RIGHT. IT MIGHT WORK!
To operate any of these units legally
in Australia you must hold an
amateur operator's license.
SPECIALIZED COMM. TECHNIQUES
FOR THE RADIO AMATEUR (ARRL)
Has intro to specialized communications
& individual chapters on: ATV, SSTV. FAX.
RTTY. Space Comms, 8 lasers, digital comm.
PCM, time div multiplex, speech recog ccts
plus appendix with ASCII & satellite data.
Cat B-2230 .. .. . . . . 54 gg
MIDLAND: FAMOUS
i the world over
L FOR CB RADIO
MULTI 2000A 2m SS8/FM/CW TRANSCEIVER
For the discerning amateur who wants the ultimate
m 2m gear. Transceiver is base or mobile, from
144 8 148 MHz m 10kHz steps. 1W or 10W PEP
electronics for electrical
TRADES (LOWE)
A standard text for electrical trades, but
also invaluable as a reference for the
layman, hobyist. Basically elementary
with review questions in each section: ’
Cat B-3212 . cc qi
MULTI 7 2m FM TRANSCEIVER
23 channel transceiver (comes with channel 40
146.00MHz) fitted, allows great flexibility at low
cost - you determine which channels you want.
If ordered with set. additional xtals S6 per set.
Cat D 3007 . S189.0
MIDLAND 13-830 AM
The transceiver for the budget
conscious novice. The easiest
O way to get on the air. Full 23
I channels, with noise filter
and S/RF meter. Small size
allows unit to fit neatly under
dashboard or between seats.
Cat D 1430 . S109.50
FET PRINCIPLES EXPERIMENTS AND
PROJECTS (NOLL)
Starts with basic operation 8t construct ms.
then has AC amplifiers, audio amplifiers &
oscillators, HF amplifiers 8< oscillators, rcvr
circuits, trans circuits, measurement circuits.
Cat B 1261 . S9.50
DAIWA 2m FM RECEIVER
Ideal as 2m monitor. 146-1 52MHz, 1 1 channels
plus VF0 Compact, reliable set has tuning LED
to assist difficult copying. Squelch fitted, too 12V
Cat D 2807 . $97.50
BASIC ELECTRICITY & INTRO TO
ELECTRONICS (Sams)
Basic, but detailed. Starts with fundamentals
and ends with industrial electronics. Has a
summary 8» question section at end of chapter
Cat B- 1 689 . * $7 gg
MIDLAND 13-882C AM
A beautiful AM set . The 882
is probably Australia's most used
27MHz transceiver. 23 channels,
with effective ANL, delta tune,
full 5 watts input. Comes with
mounting hardware, as do all
Midland transceivers.
Xat D 1436 . $149.50
KENWOOD QR666 RECEIVER
Covers 170kHz to 30MHz in 6 bands. Bandspread.
can be used mobile, portable or base. ANL &
antenna trimmer. FET front end.
Cat 0 2866 . .. . S229.00
TTL DATA BOOK NATIONAL SEMICOND.
De^riptions. connections & specifications of
all 54 '74 (garden variety) TTL ICs, plus
additional info on other NS TTL devices
CatB 4021 . 0400
YAESU FRG-7 RECEIVER
Uses the famous Wadiey Loop principle for superb
frequency stability. 550kHz - 30MHz. 0.25uV
sens. (SSB). A truly magnificent receiver. 12/240V
Ca,D 2850 . S275.00
DIGITAL INTEGRATED CIRCUITS -Par
1. TTL. (De Muiderkring)
Similar to the NS TTL book, but contains
cross references to type numbers, etc, plus
ha$ information in 4 languages - Dutch
English. French 81 German
Cat B-2070 . c* c„
MIDLAND 13-892 SSB/AM
When you go SSB, you'll wonder
where the noise went1 All the
punch you need to get through
when AM sets wouldn't have a
chance. USB & LSB plus AM,
5 watts input. RF gain control.
Cat D 1700 . $239.50
IC0M IC202 2m PORTABLE TRANSCEIVER
SSB & CW transceiver designed mainly for portable
tropo DX work (of course, you can use it for a couple
of other uses') Covers 144 145MHz. whip ant. me.
Cat 0 3040 . S183.00
PHILIPS GENERAL CATALOG. 1976.
Have you been using a 1975 catalog? Throw it
out' You cannot afford to use out of date data
Tim gives details of Philips' Elect Comp 81
Materials Divn. Cat B 4010 $3 45
INCREDIBLY CHEAP MOBILE
ANTENNAS FOR 27, 52 8«144
Latest design mobile whips for
27, 52 & 144MHz. Stainless
steel whips, with heavy duty
'Cycolac' plastic base incorp
orating a PL259 plug for easy
mounting.
*********
Tftey'fte back
SANYO HAND HELD 27MHz 5 WATTERS.
These fantastic transceivers are back in stock:
Now all the people who were disappointed before
can grab one. Quick. (They won't last this time
?,h?r- J_Cat D1142 . $89.00
27MHz: Includes loading coil
in base, takes up to 50 watts
input. Rugged; VSWR less
than 1.5:1. Ridiculously
priced, incredible value.
Cat 046 15 . $9.75
BINDERS FOR MAGAZINES
Keep your electronic magazines tidy in
a Dick Smith Binder Holds EA. ET or AR.
takes a full 12 issues. Easy to fit or remove.
Cat B 4045 . $4.50
WOW! LOOK AT THIS
__52MHz: 1/4 wavelength, 1.24m
high. VSWR less than 1.5:1.
rugged, rustproof design. Comes
apart for easy storage. A
bargain and a beauty!
Cat D 4614 . $9.50
INCREDIBLE VALUE FOR A 27MHz TRANSCEIVER!
k I've been selling almost identical transceivers for S1 19
B Here s one ,or onlV S89.50. A fantastic little unit, full 23
B channels, AM, with power output and signal strength
H meter, squelch controls, complete with mounting hardware
■ and instruction book. All you do is add power and an
antenna and you're on the air. Performance is equal to man^
of the higher priced rigs on the market. Save a bundle now'
^ 0 1149 .
3 colour Great Circle Map of the World, printed
on deluxe art paper. A must for every ham shack!
Designed with Sydney at the centre , works as well
for Brisbane. Melbourne, Adelaide & Hobart. Lists
Q code, amateur prefixes, amateui frequencies.
Mount a rotator indicator through the centre &
have direct bearing readout' Supplied free to
Radio Clubs (limit one) simply apply on
letterhead. Cat D 5402 . S3 00
144MHz: 1/4 wavelength (just
47.5cm high!) SWR 1.5:1, 52
ohms. Short on length 8< price.
Cat D-4610 . $6.75
144MHz 5/8 wavelength (1.19m
high) will take a whopping 200W
input' High power, low price.
Cat 04611 . S9.75
HOW DO YOU KEEP THJ
ANTENA UP?
Use a base: this deluxe
gutter grip is sturdy.
easy to fit. Non *|ig
corroding alloy. ffv:
Cat 0-4625 . . S6.9G^M
FANTASTIC 150 IN 1 - THE ULTIMATE'
A magnificent educational kit. Probably the
only two things you can’t make with this set
are a television set and an atom bomb No
soldering required (safe') and eveiyth.ng is
supplied in a sturdy wooden case The kit
ab0U* everVlhing you could want.
Wl ,,1.° y. . S36.95.
BUILD A 100 *
TRANSISTOR }
RADIO s12.50 *
IS THERE A BUDOING EINSTEIN IN THE HOUSE?
Find out with these fantastic constructors kits. Both
^ offer absolutely incredible value for money (just look
jJ. at how many thmgs you can build') Both are 101 ,
t safe And both are ideal Christmas gifts for anyone
^ who would like to dabble with electronics
*
± SR3A DELUXE 105 IN I KIT
J 105 d',,erenl circuits to build, all in a 120 page instructior
manual Includes solar cell, microphone. 2 speakers, morse
CENTRE LOADED MINI WHIP!
FOR 27MHz.
You asked for '’em so we got'em.
Gutter grippei or magnetic base,
both centre loaded, just 550mm
high. Easy to store adjustable
for precise SWR
Gutter Gripper Cat 0441 1 .. SI 7.50
Magnetic Base Cat 0 4412 .. S19.50
Trunk lip mount:
■ Semi fixed (no hole)
’ mount on boot or
bonnet lid, or can be
used through roof with
small hole. Economical!
Cat 0 4619 .. .. S3. 75
Or a magnetic base:
Incredibly powerful
magnet. No need to
drill ANY holes. Easy
to remove & stow /
away. With nylon I
gasket to prevent * *
scratching.
Cat 04623 .. .. $9.75
lYOU CAN BUILD THIS EVEN IF
•YOU'VE NEVER SEEN A RESISTOR!
A transistor radio kit containing 2 integrated
circuits which themselves contain the equiv
alent of over 50 transistors each. It's a great
way to learn' A beginner can put this kit
together in an evening and you don't end
up with a piece of |unk. It's a working radio.
Cat K 1032 . $19 5Q
RING WANTED ITEMS IN RED! fe*
FOR THE HANDYMAN
WANT TO IMPROVE COMMUNICATIONS
IN YOUR HOUSEHOLD
Instal an intercom* Or two. Dick has an
intercom to suit every need. From a simple
2 station (e.g. house to shed) up to a multi
station master system. See them today and
save your voice for shouting at Christmas.
Cat F 1020 $J
*
1200
350
IF YOU'RE READING THIS AD
YOU PROBABLY HAVE AN IRON
Soldering iron, that is. But chances are.
you've been using the same iron as
you do the guttering with If so.
try this iron for all general electronic
work, the Weller SP250 Runs from
mains, but is lightweight, has
stainless steel barrel. Ideal for
learning to solder with, too*
Cat T 1030 S9.75
KM THE AUTO ENTHUSIAST
S9f!
MONO & STEREO RADIOS
inOK ALMOST
WHEN YOU INSTALL YOUR
NEW INTERCOM .
(The one you just got above*)
You don't want to leave cables
dangling all over the place, do
vou7 Staple them to the wall
with our cable stapler* Of
course, you could also use it
for your new speaker leads.
. for the new burglar alarm
wiring, etc etc. Takes standard
staples, tensions the cable as
you go. Makes the job a dream
Cat T 5615 . S3.50
ARE YOU A CONSTRUCTIVE HANDYMAN7
If so. you might like a drill speed control. There’s only one catch
You have to build it yourself (and save lots of bickies doing so*)
But it’s m easy kit to build. So don't panic. When finished (!) it
will control the speed ol your hand drill from practically zero-up
to nearly full (normal) RPM. while maintaining useable torque
(no reference to ABC TV). Suitable tor drills up to 3A.
Cat K 3080 . 559.75
DONT BLOW A FUSE OR YOUR
COOL: You know what it’s like
trying to find fuse wire in the dark*
Replace fuses with these fantastic
little plug-tn circuit breakers. All
you do is press to re set. So simple -
anyone can install them in just a
couple of seconds. Tremendous
time saver* Cat S 5508 (8 AMP)
or CatS 5515 (15 AMP) .. S7.95
You know what's wrong with most car cassettes7
They’re made down to a price: cheap & nasty
Dick looked at these and rejected them, then
T went overseas to find a good one. He found this
quality unit using the famous Belgian Starr
mechanism. It also has a fast forward button
, something many of the cheaper units miss out
on. If you want quality, this is the cassette yqu
need Cat A 6485 . $79.00
AM/FM STEREO CAR RADIO ^
You can now receive STEREO ^
in your car with this brand new
import . A handsome unit which jA.
features full FM (MPX) stereo ^
reception and a massive 12 watts
output (2 x 6W). Has tone and jL.
balance controls, too. Push
button tuning, too. It will pick
AM/FM CAR RADIO
There's just no point in buying
an AM only car radio when for
so little extra you can be enjoy
mg the fine music and-high
fidelity of the new FM stations.
Pushbutton type, high power
output (6W) and in-dash mount up normal AM beautifully,
add up to one thing: VALUE. Speakers extra for both radios!
Cat A 5982 . . . $69.00 Cat A 5983 . $89.00
'9.15/
WHAT A BRIGHT IDEA.
Give him a fluoro lamp to put in
the car, boat or van. Clean, white
light, uses standard replaceable
tube. Can be mounted m |ust about
any position; requires 12V @* 8W
Cat X 1082 . S9.75
CREATE YOUR OWN MOOD BY
MOOOLIGHTING
Sure you can make one but for
this price7 It's neat, compact and
functional You would be hard
pressed to make one as good as this!
The 'Moonglo' light dimmer will
handle incandescent or fluoro
lamps up to a total o< 500VA.
and RFI suppression is fitted.
Installation is simple (but should
be done by an electrician)
Cat X 1112 . S6.90
This fantastic dimmer is much/
much more than JUST a dimmer*
It will automatically turn youi
lights on to a pre determined level
as night advances. Imagine the
advantages of returning home to
a house which looks occupied
Think of the security applications.
Then look at the puce. UNDER
S10.00. Incredible is hardly the word**
Cat X 1113 . S9.95
★★★★★★★★★★★★
S
DICK SMITH HAS THE MA1002 ALARM CLOCK KIT
DOLLARS CHEAPER THAN HIS COMPETITORS
The very latest 'clock on a chip' <i 4 digit alaim clock
built onto the one 1C chip including the display! T!ie
chip is pre assembled on a PCB (you don’t have to
worry about soldering the 1C). All you need add is a
set ol switches U control time setting, etc. Simple!
V-
SEE EA OEC76
^YOU CAN SAVE MONEY WITH THE
8- DICK SMITH KIT! If purchased separately
from our competitors, parts would cost around S21.00
,C A Dick's kit S 18 50* A bargain. And we supply the
module. 6 miniature push buttons, alarm on' off slider
switch special transformer and full data sheets.
Cat K 3434 . S18.50
If you only want the module, we have that for just
S1 1.50. (Picture shown at top) The board contains
all the parts. See E.A\ December for circuit details.
Cat X 1052 . S1 1.50
A transformer to suit this chip 8i circuit.
Cat M 2822 . S3.75
powfr pius! roue yoursflf
DO YOU LIKE MUSIC IN YOUR CAR?
How about LOUD music? Fan tastic. We have
something for you a car stereo power booster It's
a sad fact of life that most car stereos have just a
couple of watts output. And that's barely enough to
get above road noise, let alone sound like hi-fi.
The stereo power booster is simply installed in your
speaker leads (powered by car battery) And instead
of your measly couple of watts, you get a full 10 watts
per channel. That's as much as many home stereos!
Easy installation (instructions supplied) just a few
minutes work and you can be driving around the bend (7)
Cat A 6612 . . S27.50
HOME MECHANICS: HAVE WE GOT A CHRISTMAS FOR YOU! ;
You don't need to be told how much \
your car is costing these days. You
want to save some money, right?
Solution: Do your own tuning!
It’s easier than you might think.
Especially with a tune up analyser
such as this -little beauty. In
conjunction with a timing light,
you can do all electrical tuning
and carburettor adjustment in
just a couple of hours. You’ll have
paid for the units after just a
couple of tunes in saved petrol
alone. Checks RPM. dwell.
points, volts, current, etc. 5/1
And a timing light: Not your average
neon types that have trouble lighting
up a pinhead, these are powered
xenon (white flash) types with pistol
grip. Invaluable tuning aid.
TUNE UP ANALYZER
COMPLETE WITH LEAOS
Cat A 8512 . $29.50
XENON TIMING LIGHT
Cat A 8505 . S19.75
tO WATTS
HE CONSTRUCTOR
The ULTIMATE TV Game Kit :
with sound and full digital scoring!
suns.
There are TV Games and there are TV games ... but there is only one
SELECTA GAME*
This game conforms exactly to the original ET design and specifications
there have been no cost-cutting corners or inferior substitutes.
There are six selectable games, selectable bat sizes, selectable ball size;
selectable angles, and you get both sound and full scoring. The kit is
easy to build; it is complete to the last detail (inc. front panel).
Demand is great; stocks are limited. All orders filled in strict priority of receipt.
You COULD be playing TV games tonight. (The ratings periods are over for a few months
so the programs are pretty lousy. Show your disgust by playing TV games instead1)
SEE ETI NOV 76
CONTROL UNIT ONLY SHOWN.
SEPARATE ARMCHAIR CONTROLS SUPPLIED
S0PCR8 PLAYMASTBR TW/R25
8950*
SEE EA SEPT 76
SPECIFICATIONS
Powei:
25 ♦ 25W RMS (8 ohms)
Freq. response.
30Hz 20kHz (IdB. RIAA)
Channel Separation:
46dB (» 1kHz, 33dB @> 10kHz
Input Sensitivity:
Phono at 1kHz: 2mV, 56k
Overload at 1kHz 120mV.
High level 150mV. 36k.
Hum & Noise
70d8 unweighted
THD:
less than 0.2%
typically less than 0.05"-
GIVE YOURSELF TWO CHRISTMAS PRESENTS! If you huild the Damping Factor
Playmastet Twin 25, you will save at least one hundred dollars (or
more) on a commercial amplifier with similar specifications So you
would get two Christmas presents a superb new 25W per channel
amplifier AND the S100 in your pocket that you saved*
MVSKMOWUt
r. . .
Cat K 3140
TOY ORGAN
WITH DICK'S EXCLUSIVE
CONSTRUCTION MANUAL
greater than 60 @ 1kHz
greater t! an 30@30Hz
Stability
Unconditional
HAVE THE WILDEST CHRISTMAS PARTY
ON THE BLOCK!
Don't just have coloured lights, hava wild, with it
modulated lights just like the discos have. How
do they do it7 with a colour organ like the
Musicolour It takes an audio signal (e.g. from
youi speaker terminals) and converts it to a drive
for jrdinary coloured lights. You can have 3
different colours 1 for each of the channels for
high, medium and low frequencies. Unreal!
By the way - did you know that you can use a
Musicoloui to modulate ordinary 240V Christmas
tree lights - just connect them to the Musicolour
middle' channel and connect to your hi-fi. Youi
Christmas tree will then light up to your music
SEE ETI AUG 76
LIBERACE - EAT YOUR HEART OUT!
If you've always wanted to play a musical instrument, here's
youi big chance AFTER you've built it* And we don’t
really know what is easier building or playing* Anyone who
can use a soldering iron can make this mini-organ. And anyone
can play it - all you do is touch your finger on the special keys
and presto! You can play tunes instantly. The kit is complete
excepi for the wooden case we thought you would like to
please yourself there. Happy playing Cat. K 3430 .. .. S24.75
iS2150
DICK SMITH ELECTRONICS GROUP
HEAD OFFICE: Phone 439 5311. Telex AA20036. Cable ‘Diksmit’ Sydney
MAIL ORDERS: P.O. Bok 747, Crow* Nest, N.S.W. 2065
N.S.W. BRANCHES: GORE HILL-162 Pacific Hwy, 439 5311
SYDNEY- 125 York St, 29 1126 BANKSTOWff-361 Hume Hwy., 709 6600
OLD— 166 Logan Rd., Buranda 391 6233
INTERSTATE BRANCHES: y|£ — 656 Bridge Rd., Richmond 42 1614
SEE ETI
AUG 75
WANT TO FIX YOUR
OWN COLOUR TV?
Many hobbyists have the
knowledge to fix their
own colour TVs, but
most lack the gear. Here's
one item that won't break
the bank a crosshatch 81
dot generator, essential
for convergence 81 purity
adjustment And it's
simple to make.
Cat K 3290 . .. $21.50
DICK SMITH DEALERS:
x Aero Electronics, Hobart (34 8232)
A Veneman & Wyatt, Darwin (81 3491)
ft- \ Wills & Co., Launceston (31 5688)
I Hunts Electronics. Toowoomba(32 6944)
A.E. Cooling, Elizabeth South(255 2249)
fUf The Record Centre, Griffith (621 577)
r? Altronics Parts, 105 Stirling St,
Perth W.A. 6000 Ph 28 1599 ,
Dealers prices mav be higher due to transport costs.
f + + +
(IILO RE DAS
» FOR THE HI FI'ER
*
*
*
*
*
*
A fantastic 'start up' deck to begin your
hi-fi system — or a great 'dubbing' deck
for serious audiophiles.
WATTMASTER
STEREO CASSETTE DECK WITH AUTO STOP
^ This real beaut deck has slider level controls, three neat
switches (tape select normal or Cr02, noise cut to
J eliminate hiss; and power on/off). Has piano key operat-
'on with auto stop feature. Microphone inputs (mics
y* supplied) or phono jack inputs. Stereo headphone outlet.
J r fa2t2iC,deCk ,or ,he price ~ limi,ed quantities only!
* Cat A 3682 . . . $99 90
* BASF HOBBY BOXES
Cat A 3682
WHATEVER HAPPENED
TO INFLATION. ITS DEAD!
LAST YEAR I SOLO SIMILAR
DECKS FOR $139.95. LOOK
AT THE PRICE NOW'
ARGO Dl KIS AN TAH OHO HO *
\p Fantastic Speaker Kit hi h changer
^Hk Hnw nn vnu ninnc a cocn/cm _ _ _ _
If you own a tape recorder or cassette deck, you'll need to v-'
splice tapes. Don't try to do it with a razor blade and sticky
tape - join the professionals. Use a BASF hobby box.
Don't forget Dick's full range of tapes & accessories for that
last minute Christmas gift that you forgot to buy'
FOR THE LISTEHER - —
J CASSETTE HOBBY BOX s1215
^ Contains all you'll need to properly
^ look after your valuable cassettes'
With splicing template, non magnetic
. scissors & tweezers (very important for
~ noise-free splices) Philips & flat screw
drivers, spicing tape & dispenser, 10m
w of leader tape, clips, pressure pads and
* spare screws. Ideal for making party
yL tapes, sound effects or special effects'
^ Cat C 3500 . $12.15
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
-
. VALUE PLUS! PACKSON' AM/FM
** ... WITH CASSETTE RECORDER
You can record direct from ^
%. the radio - no leads or
••se the inbuilt condenser
Cat A 4016
REEL TO REEL HOBBY BOX $^75
Similar to the cassette hobby box, but has gear just for
the reel to- reel set. Like a marking pencil, splicer, tape,
red, green & white leader tape, stop foil, spool labels,
tape clips, etc. The complete editing kit!
Cat. C-3502 . jj 75
AM-FM AC
LATEST LOOK AM/FM RADIO
You can play it on the beach, you can play it
in the home. Dual power for economy (240V
mains or internal batteries) and dual band for
versatmty. AM for normal DJ & news stations
FM for fine music stations. Absolutely mad
give away price for such a fine looker & good
performer. It sounds as good as it looks!
C>t A4320 . . . $19.95
*4
HOW DO YOU JUDGE A SPEAKER?
The ultimate test of any speaker is how it sounds to you
After all, you're the one who has to live with it.
These sound great with just about any speaker.
But there are other considerations. Like how much room
they will take up. Can they be fitted into a small space’
These are small.
How do they look. Will they tone in to the rest of my room?
They look great. (You can change the colour of the baffle)
And are they expensive.’ It's one thing to buy a good speaker
another to pay a month's wages for it!
These are very reasonable.
Some kits are hard to put together. Do you have to have a
degree to put them together?
These are dead easy.
Okay. I'm convinced. Where do I see these fabulous speakers?
Where else but a Dick Smith store or dealer.
You can please yourself what speaker
you put in this box . . . But Dick has
a couple which would be ideal'
Cat C-2100: 28Hz - 20kHz response,
30 watts rating. Dual impedance, 4 or
8 ohms. Huge 16oz magnet' Twin
cone for optimum performance.
CatC 2012: Famous C8MX . 10W
<£ / K|| (fros) 8 ohms, dual cone. Resp.
* «.vTV approx 30Hz 18kHz. Recommended.
IS YOUR OLD PLAYER CLAPPED OUT?
Did you know that it's easy to change to a
brand new Garrard. Your records will love
you for it!
These fully automatic turntables can stack
up to 6 records, they have a sapphire stylus
in their ceramic cartridge, and have a cueing
lift. Why put up with a worn-out player
any longer. Get one of these mighty Garrards
today 1 r~
Cat A 3036 . . .. $17.50 ^
Don't forget Dick's full range of 4^
1 record accessories and equipment
for that last-minute Christmas gift
SANTA SMITH 81 STAFF WOULD
LIKE TO WISH ALL CUSTOMERS
AND FRIENDS A MERRY
CHRISTMAS AND A SAFE AND
PROSPEROUS NEW YEAR.
* Specialty
designed for Australia
* Opens dew listening
realms * Complete
PUP coverage
VHF all band communicator.
Covers bands below, AC/DC.
compact portable. LEQ light
for tuning. Earphone socket.
NOW ONLY
*44.90 %
SPECIAL
135-
DICK SMITH ELECTRONICS GROUP
™OOOffiCG : Phone 439 5311. Telex AA20036. Coble Diksmit Sydney.
Moil Orders: R O. Box 747. Crows Nest. N.S. W.. 2065.
N.S.W. Brooches .GORE HILL-162 Pocifk Highwoy.439 5311. ‘g*
SYDNEY- 125 Y0,k St. 2? 1124. BANKSTOWN - 361 Hume Hwy.. 709 6600.
Interstate Branches- QL0 ' ,46 Lo9on Rd Bu,°"d° 391 «33.
VIC. -656 Bridge Rd.. Richmond. 42 1614.
Cat. D 2833
EXCLUSIVE VJLE STATION
GUIDE OUCt ROMOS
530 - 1600kHz: Normal AM broadcast band. All
your normal local broadcast stations.
54 - 88MHz TV, Fire brigade. Ambulance, Police,
Business Radios, etc.
88 - 108MHz: New FM broadcast band.
108 - 136MHz: AIR band all aircraft (tiger moths to
jumbos, tower, etc)
217MHz: Amateurs, marine VHF, harbour control.
Taxis, Police, Road Patrols, etc etc;
LUXTONi AM/VHF
RECEIVER
Same band coverage as above receiver,
incredible value for such wide range.
‘Luxtone' AM FM-VHF receiver
operates on AC/batteries, smart
appearnace and comes complete with
earphone and batteries. All solid
state, robust construction.
Cat 0-2840 . $29.90
$29. 90
LOOKS WORKS BETTER
THAN RABBITS EARS:
Deluxe TV antenna for indoor use in
primary reception areas Ideal for colour
or BSW use, standard connector
Cat L-4012 . $8.90
VHF AIRCRAFT
RADIO WITH
AM BAHD
$12.50
Handy pocket radio
allowes you to listen
international air-
band (110-136
MHz). You can hear
the control tower,
automatic weather S
landing information,
aircraft approach and
departure instructions,
aircraft to aircraft etc.
Ideal for flying stude-
FOR THE TECHHICIAH
*
INCREDIBLY HANDY LITTLE DC VOLTMETER
DIGITAL READOUT IN END OF PROBE • • •
Ideal for service, developmental work etc, this
fantastic little DC voltmeter has a 3 digit readout
in the end. Ideal for working in close when you
can't afford to take your eyes off the circuit -
one flash and you're ash!
3 range*. 20V, 200V S 1000V . Battery powered.
Cat Q 1445 . ...... .. .. $89.50
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
SAVE 33%%
50
Uo*
HIGH SPEED STEEL MINIATURE DRILLS
FOR PC BOARDS:
Just right for component leads, no. 60 (,04in)
won't be too sloppy or too tight.
Cat T4820 .. . $0.50
Or a little smaller: A no. 65 (,033in) ideal for
small leads (especially 1C pins).
Cat T 4825 . $0.50
SIGNAL INJECTOR
YOU CAN SERVICE ON THE CHEAP!
Very economic service signal injector puts
out harmonics way up into the RF region.
An invaluable service tool (at twice the price!)
J^atQ-1270 . $4.75
DICK SMITH DEALERS
A.E. Cooling, Elizabeth South. S.A. Ph 255 2249
Veneman & Wyatt, Stuart Park, N T. Ph 81-3491
Aero Electronics. Hobart, Tas. Ph 34-8232
Wills & Co, Launceston, Tas. Ph 31 5688
Hunts Electronics, Toowoomba, Qld. Ph 32-6944
The Record Centre, Griffith, N.S.W. Ph 62 1577
Altronics Parts, Perth. W.A. Ph 28 1599. • I
Dealers prices may be slightly higher
due to transport costs. I
J_T>«n«Ullen: M«llo r»«d«r». h.r,’, . to Qicll i, sinli. Ho Mo Mo, ■
POSTAL CHARGES
cunBunilBP ORDER VALUE CHARGE
Mon -Fri: 9 to 5.30 !o° $2499 $1.50 pac^ng^NO^HandluTg CHARGE ^
Sat •' 9 to 12. 0 JJJ-JJ jfK is si 00. we despatch -freight-
$50 to $99.99 $3.50 ON’ AND YOU PAY WHEN YOU
GM— $100 Of more $5.00 RECEIVE THE GOODS
hnnUrnrrl 1 F0R C ° 0 SEN0 $T4° EXTRA PLUS S3 00 DEPOSIT.
ocinHcorcJ j minimum mail order amount is $sv
★★★★★★★★★★★★★★★★ k
Circuit & Design Ideas
Conducted by Ian Pogson
Interesting circuit ideas and design notes. MtocMd I™"*** ** ^
laboratory. ™s^nabili^cannotbeaccepted Your contributions are welcome, and will be paid for if used.
Designing optimum-Q and small inductors
Optimum Q is achieved in an inductor
when its length and diameter are equal.
This table will serve as a guide when
designing high-Q inductors for RF cir¬
cuits. It gives maximum turns and induc¬
tance for various wire gauges when
close-wound in a single layer.
Higher Qs will be obtained if the turns
Wire Diameter & Length (inches)
AWG 1/8 1/4 3/8
are spaced at one wire diameter. This
results in half the turns and one quarter
of the inductance listed in the table.
Should an intermediate inductance or
number of turns be desired, the factor,
K, at the bottom of each column can be
used for calculation from the formula
L= KT.
16
18
20
22
24
26
28
30
T
L*
T
L*
T
L#
T
L*
T
L*
T
L*
T
L*
T
L*
.108
.233
.414
1/2
8
.552
10%
.950
5/8
3/4
3
6%
10
13
.0194
.182
.647
1.46
4
8
12
16%
.0345
.276
.931
2.35
5
10
15
20%
.0539
.431
1.46
3.62
6%
13
19%
25%
.091
.728
2.46
5.61
8
16
24
32
.138
1.10
3.72
8.83
10
20
30
40
.215
1.72
5.82
13.8
.00215
.00431
.00647
.001
10
12
16
1.08
1.86
4.41
13
15%
21
1.82
3.11
7.60
16%
19%
26
2.93
4.92
11.7
20
24%
33
4.31
7.76
18.8
25
30%
41
6.74
12.0
29.0
32%
38% *
51
11.4
19.2
44.8
40
48
64
17.2
29.8
70.6
50
60
80
27.0
46.5
110
.0108
.0129
.01
When small inductors are needed, for
RF chokes or HF filter networks, it is
frequently convenient to wind them on
composition (carbon) resistors. The table
shows inductances for various wire sizes
when close-wound on common resistor
bodies. The resistor value should be
above 4.7k for the low value inductances
and above 47k for the higher values,
unless low Q is desired.
The number of turns listed leaves a lit¬
tle space at the end of the resistor body
to file small notches in order to guide the
coil wire down to the resistor lead while
not allowing the coil turns to fall off the
•Inductance. L. is in microhenries.
Shunt stabilised power supply
(By
R. E.
Martin,
in "Popular.
Elec-
tronics
Wire
Resister
Size
AWG
%W
%w
1W
2W
T
3
7
11
14
20
L*
.013
.097
.32
.63
T
4
8
13
17
22
L*
.023
.13
.45
.92
T
5
10
17
22
24
L*
.036
.20
.76
1.5
T
6
12
21
27
26
L#
.051
.29
1.2
2.3
T
8
15
26
33
28
L*
.092
.45
1.8
3.5
T
9
19
32
41
30
L#
.12
.72
2.7
5.4
T
11
22
39
50
32
L*
.17
.96
4.0
8.0
T
14
28
49
62
34
L*
.28
1.6
6.3
12
T
18
34
60
77
36
L*
.46
2.3
9.5
19
This circuit offers an improved power
handling capacity over a simple zener
stabilised circuit. It is short-circuit proof
and less likely to damage delicate loads
in the event of a fault in the supply. In
many cases less power will be dissipated,
by the regulating transistor, than in con¬
ventional series stabilisers. In the circuit
shown, a feedback amplifier has been
added to compare the output and zener
voltages. The regulating transistor carries
current equal to the difference between
maximum and instantaneous currents.
Therefore, if the load normally takes
close to maximum current, the power
dissipation will be low and a cheaper
transistor may be used, particularly if the
unregulated input voltage is very much
larger than the required output voltage.
(By J. Suter, in "Wireless World".)
ELECTRONICS Australia, December, 1976
•Inductance, L, is in microhenries.
TTL decade counter
divides by any integer
In many applications a pulse train must
be divided by a fixed integer. For exam¬
ple, digital clocks often divide the line
frequency by 50 to obtain a 1 Hz output,
and time-base generators divide a crystal
oscillator frequency down to several sta¬
ble low frequency outputs. If the integer
is 10 or less, just one 7490 TTL decade
counter can handle the division.
Usually frequency division in TTL cir¬
cuits is accomplished by using binary
counters and logic gates. To divide by
83
I
DIGITAL AUTO CLOCK
KIT 51- SO
ONLY
Let your car. van, boat, caravan, truck, aircraft or any other vehicle join the Digital
Revolution with our new Digital Auto Clock
FEATURES
y4ZTLSpSCrprPERnAr * TWO-WIRE NON-POLARIZED POWER INPUT • BRIGHT
.27 RED LED DISPLAY . DISPLAY BLANKS WHEN IGNITION TURNED OFF . 12 OR 24
HOUR TIME DISPLAY • QUARTZ CRYSTAL ACCURACY TO WITHIN .002% (ADJUSTABLE) •
HIGH-TEMP ABS PLASTIC CASE WITH MOUNTING BRACKET • CAN BE MOUNTED ON OR UNDER
VEHICLE DASH • BATTERY BACK-UP FOR POWER FAILURE OR MOVING FROM HOUSE TO CAR
ETC • EASY TIME SETTING VIA HIDDEN SWITCHES IN FRONT OF CASE • VOLTAGE SPIKE AND
NOISE SUPPRESSING CIRCUITRY
Complete kit includes all parts, displays, etched and drilled PC Boards. Case and mounting bracket (less 9V
transistor battery).
ALSO AVAILABLE WITH 36 ' DISPLAYS: KIT SI-204 . $33.95 ,w „ abo„. /
ALPHA MODEL DMM-1ER
DIGITAL MULTIMETER KIT
4-DIGIT DECADE COUNTER
The Decade Counter is a basis for a wide variety of
instruments.
• On-chip internal oscillator for scanning speed
• Overflow and count-ex tend outputs
• Transfer, reset, count, blanking and true compliment
control inputs
• Circuit board can be cascaded to 8 12 16 digits
• Kit includes all components. PCB’s. LED displays
(you select the size) and complete instructions
KIT SI 12A (with 0.27" displays) . . . S23.95
KIT SI-12B (with 0.50" displays) . S27.95
Plus $2.95 Airmail
post/registration
Measures:
AC VOLTAGE
DC VOLTAGE
AC CURRENT
DC CURRENT
RESISTANCE
specifications
> 40
oll\ Ih-Iwiy-ii 100 .Hill
t 5 volls In'tWITIi
AC VOLTAGE
t mtlliviili III 300 voii\ III thill' laiuprs
Input mi|iedance 10 mii',h,i„„s Accu
racy 1 Frequency Response 0
In lull scale
100 H/ 0 in
10 000 H, _ ...
10 Kli/ ui„| &0 Mi/
RESISTANCE
1 olinr lit 6 megohms Accuracy (J
CURRENT
DC current I imcroamii in 7
Accuracy t AC current t
.imp in 300 milliamps Accuracy
AC Frequency Response Same .i
AC vnl|ai|i'
DC VOLTAGE
I millivolt 600 volts in linn Mina-s
Input Impedance 10 megohms Accu
racy 0 t in 300V t hi 600V
RESOLUTION
I ohm
Tfst IE Ads ANO BATTERIES NOT INCLUDED
GENERAL
Readout 3 ihqil I E 0 Power Source
linn AA i|M'iilii|ht i si/i* trailer ics iNi
C.iil alkaline m carl x mi /inti Over range
Indication display flashes when m|nTt
i'klivm h valor nl ranqe selected Polarity
Indication aqtumatic 'neqalivi- voltaqr
.mil t.iirrenl indicated tty display I Si/e
1 » 3 4 a 16 Weight 8 n/
Case IihiIi impact Cyculac Color Red
FM WIRELESS MIC.
Kit SI -36 is a completely new design in
FM wireless transmitters. A unique PC
foil layout eliminates 'the need for a
wire-wound coil. Use with any dynamic
type microphone to broadcast over the
FM band. Use as an Intercom, Baby
Alert, Magic Shows, School Science
Project etc Transmitting frequency
adjustable via a trimmer cap.
Battery and microphone nut included
Frequency Range 50 MH/ to 200 MH/
Output Power 100 milliwatt with 9 volt
Max Output Power • 1 watt with 50 volt
Current Consumption 10 mA to 50 mA max
Input Impedance Maximum 22 K ohms.
Size 1 5 in.
•Intermittent
c 2 0 m
KIT SI-3B
$395
DISPLAY LED'!
w *
FND 70
FND 357
F NO 503
FND 510
FND 800
FND 810
DL33MMB
DL 747
XAN 654
XAN 664
1 20 ea
1 50 ea
1 60 ea
3 95 ea.
3 95 ea
1 4b ea
2 95 ea
2.95 ea.
2 75 ea
5 S 3 95
5 S 565
5 S 6 95
5 S 755
5 S18 75
5 S18 75
5 S 6 75
5 SI4 25
5 S14 25
5 Si? 95
CRYSTAL TIME BASE
BO HZ OUTPUT
Here's the ideal kit for converting your AC powered digital
clock to DC operation. This unit has a 60Hz output, but is
ideal for use with clock chips such as the MM5314. MM5316.
CT7001 and others which have both 50 and 60Hz inputs
Features include Low power consumption (5mA typ), 5-15 VDC
operation, small size (1"x2"). adjustable accuracy to .005%.
Kit includes all components. PCB and easy assembly and hookup
instructions to interface with most MOS clock chips.
DISCRETE LED's
Description
Sohmim Red
Stihmim Green
Mini Red
Mini Green
Jiimlro Red
JnmlK) Orange
Jumlro Yellow
Jumtio Green
100
1000
1(J00
1000
13.50
1350
22 00
22 00
21 00
’ Denotes device has no decimal iioint
C C Common Cathqde CA Common Amnle
CLOCK CHIPS
LINEAR 1C*!
Micro Power Op Amp
2 Watt Audio Amp
Timer
Phase Locked Loop
PLL Tone Decoder
Voltage Regulator
Op Amp
Op Amp
5V/1A V Regulator
5V Regulator TO-220
12V Regulator T0-220
15V Regulator T0-3
24V Regulator TO 3
IK Static RAM
10/S 9.0(0
10/S 9.00
10/S 5 50
1Q/S16 00
10/S12 70
10/S 4 95
10/S 2.25
10/S 2 25
10/S 9 50
10/S 9 00
10/S 9.00
10/S1 1 50
10/S1 1.50
10/S21.50
9-DIGIT DISPLAY
OH spec devices the only fault we found ,vith them is that some
digits m.jy |»e slightly dimmer than others All segments light At
1 1 cents a digit you can't lose Ideal foi a mini digital clock, stop
watch oi calculator COM. CATHODE
SPECIAL — SO. 99 each .
3 for $2.60
LED DRIVER ICs
Ah
75491 Quad Segment Driver
75492 Hex Digit Driver
SO 39
SO 49
MM5314
MM5316
6 -digit. 12 24 Hr . 50 60H/. Multiplexed
?4-pin dip.
4 6 digit. 12'24Hi . 50 60H/. Alarm. Sn/ .
40-pm dip.
6 -digit Alarm. Sn/ . 12 Hr 60H/.
24 Hr 50H/. 28 pin
4 -diqit direct LED drive. Alarm. Sn/ .
Radio timer, non-multiplex, 40-pin
PCB for MK50252. etched and drilled
PCB for MK50381. etched and drilled,
.. also accommodates 4 x FND 70
All clock chips supplied with data sheets
MK 50252
M K 5038 1
S695
S3 95
SPECIAL CIRCUITS
MK5002 4 -digit decade counter 'latch/decoder. 7-seg and
BDC outputs. 28-pin dip with data
MK5005 4 -digit decade counter latdh /decoder . 7-segment
output curtly. 24-pin dip. with data
MK5007 4 digit decade 'counter /latch /decoder with BCD
outputs only. 16-pin dip with data
OOPB! WE RAN OUT OF SPACE _
to list many other kits and components No worry, they are all
in our flyers which absent with every order However if you want
the flyers only, send two International Reply Coupons and we ll rush
them to you via Airmail *
prices are listed m Australian dollars Please add postage where shown We pay Airmail postage on all other items
Money Order in which case original receipt should he enclosed with order
NOTE DUTY MAY BE PAYABLE ON GOODS IMPORTED
r by International Postal
MINIMUM ORDER AS5 00 PLEASE
ELECTRONICS Australia, December, 1976
sabtronics
PO BOX 64683 DALLAS. TX 75206, US. A.
TELEPHONE (214) 369 7309
CIRCUIT ft DESIGN IDEAS
/*'~*'* .Mfeftfcar--
OPERATION OF 7490 1C AS A DIVIDE-BY-N COUNTER
DIVISOR
N
INPUT
PIN No.
OUTPUT
PIN No.
EXTERNAL CONNECTIO
14
12
PIN 2 OR 3 LOW
2
PIN 8 TO PIN 2
3
1
8
PIN 9 TO PIN 3
4
1
8
PIN 1 1 TO PINS 2 AND 3
5
1
11
PIN 2 OR 3 LOW
14
8
PIN 12 TO PIN 1
PIN 9 TO PIN 2
6
PIN 8 TO PIN 3
1
12
PIN 1 1 TO PIN 14
PIN 12 TO PIN 2
7
PIN 9 TO PIN 3
PIN 12 TO PINS 1
8
14
8
PIN 1 1 TO PINS 2 AND 3
PIN 12 TO PINS 1 AND 2
9
14
1 1
PIN 1 1 TO PIN 3
1 1
PIN 12 TO PIN 1
10
14
PIN 2 OR 3 LOW
Double-pole battery time switch
Designed to switch off battery-
operated equipment automatically after
about seven minutes, this circuit per¬
forms its function with a very low current
drain on the battery. It was made up for
use in the Solid State Multimeter
described in the April, 1976 issue.
With a current drain of its own of only
350uA, it can switch at least 20mA to the
equipment which it controls. When it
switches off, the standby current it uses,
less than 2uA, has a negligible effect on
battery life.
Referring to the circuit, TR5 and TR6
perform the switching function. They
receive their drive from the TR1, ikz
Darlington pair through the common
collector load resistor. When the push¬
button is pressed, Cl charges via R9 and
the base-emitter junctions of TR5 and
TR6 turn on. As the charge across Cl
increases, TR1, TR2 turn on by current
through R4.
When the push-button is released, the
charge across Cl slowly leak® a way
through R4 and continues to hold TR1,
TR2 on, and in turn, hold TR5 and TR6
on. All this time, TR3, TR4 are biased off
by the effects of R5 and the saturated
TR1, TR2 pair. These conditions remain
uhtil the potential across Cl falls to about
1.5V.
(By Mr C. Christensen, 17 Centaur
Street, Redcliffe, Qld 4020.)
BATTERY +9V
N-i.e., to get one output pulse for every
N input pulses— the logic gates are con¬
nected so that the counter is reset when
the Nth pulse is counted. The most sig¬
nificant bit is used as the output, because
it makes the high-to-low clocking transi¬
tion only once for every N input pulses.
If it is necessary to have an output pulse
of a specific length, then a monostable
may be triggered when the Nth pulse is
detected.
The disadvantage of this division tech¬
nique is that even for divisors less than
10 two l^s are required, a binary counter
and a gate. But a pulse train can be
divided by any integer between 2 and 10
by use of just one 7490 TTL decade coun¬
ter 1C, owing partly to its divide-by-2 and
divide-by-5 stages and partly to its inter¬
nal ANDed reset, which lets it reset only
when both pin 2 and pin 3 are high.
The counter can be made to reset on
any count from 2 to 10 by appropriate
connections of, the pins. The necessary
interconnections for each value of N are
shown in the table. For example, if
division by 7 is desired, the 7490 is wired
as shown in the figure. The input and out¬
put pulse trains for this configuration are
also shown. If a larger division is
required, it is only necessary to cascade
several stages together, provided the
divisor has factors that are all less than
10.
(By T. Durgavich and D. Abrams, in
" Electronics").
BATTERY 0V
O G (SEE TEXT)
BATTERY -9V
FREE OFFER!!!
Free offer of 5 new branded BC548 transistors For every
order over $10, This month only. Take advantage of
this free offer now! Don't delay! special purchase of
fresh stock switches and electrolytics. We can sell these
at a fraction of L.st Pr.ces. Look!!! electrolytic super bar¬
gain: 2.2uf/50v Single Ended. Top aual.ty-20 for ■ $ 1
(S.E.) is single ended type. (P) is pigtail type. 1 00uf / 10v
S.E. -10 for $1. 220uf/25v (S.E.)— 10 for H.90.
47uf/63v (S.E.)— 10 for $1.60. 33uf/16v (S.E.)— 10 for
$ 1 . 47uf / 50v (S.E.)— 10 for $ 1 .40, luf /25v §.E->-1°
for 60c. 2.2uf / 25v (S.E.)-IO focr C6v5c' 2#20u^395e.V
(SE)-10 for $2. 1000uf/25v (S.E.)-6 for $2.25.
470uf/25v (S.E.)— 10 for $2.50. 47uf/350v (P)— 6 for
$3. 22uf/350v (P)-8for $3. lOuf /350v (P)— 1 0 for $3.
2 2uf/350v (P) — 1 0 for $2.25. 1uf/350v (P)— 10 for
$1.75, 1 0Ouf / 50v (S.E.)— 10 for $2 25' 47J,/50v
-(P) — 1 0 for $1.50. 22uf/50v (P)-10 for $K20.
640uf/16v (S.E.)— 10 for $3. 1 0Ouf /63v (S.E.)-IO for
$2 40 Special bulk price; 2.2uf/50v (S.E.)— 200 for
$8 Just arrived, new switches, fantastic sale of
switches. These are top quality switches. Many minia¬
ture types at incredible pr.ces. We brought a certain quan-
tity so remember, once they are sold out i thes® pr,^eSc
you've missed out. ST103A Toggle switch SPST-40c
ea MSPB206R Push button DPDT— 60c ea MSP106D
Push button SPOT— 50c ea.. MST206N Miniature Toflflle
DPDT-85C ea.. MSL203N-5 Rocker switch DPDT-65C
ea MSH203N Rocker Toggle switch DPDT— 65c ea .
MSP103C Push button S P — 30c ea.. MSP406N Minia¬
ture Toggle 4PDT-$1 ea.. MR3-3 Miniature Rotary
switch- $ 1 50 New panel meters at bargain pr.ces. Top
quality "sew" brand. SD830 Range DC 50mv size
3V4"x4V4" with blank scale to suit various projects. Ideal
for making up your own scale, sensitive movement
rugged construction, only $3.95 ea. A bargain not to
be missed! Hurry for the above specials as these are
Limited quantity specials Once they
you've missed out! Post your order today! Money beck
if not satisfied! Post and Pack is 60c. Please add extra
for large orders. _
MICRONICS
P.0. Box 175, Randwick. 2031
GETTING INTO MICROPROCESSORS!
The Mostek F8
Our survey of microprocessors continues this month with a detailed
look at the Mostek F8 chip set, and the Mostek Evaluation Kit. This
comes either as a fully assembled printed circuit board, or as a kit of
parts.
by DAVID EDWARDS
The Mostek Corporation is second
sourcing the Fairchild F8 microprocessor
chip set, which was featured in last
month's article. As noted in that article,
the F8 microprocessor set is significantly
different from other 8 bit designs we
have considered. It is manufactured
using N-channel Isoplanar MOS tech¬
nology.
The F8 system is designed primarily for
high-volume dedicated-use applications,
and does not lend itself quite as readily
as some other systems to one-off
designs. However, this system can func¬
tion with only two chips as a complete,
fully viable microcomputer system, with
Ik bytes of ROM program storage, 64
bytes of RAM, inbuilt clock and program¬
mable timer, and 32 bits of program¬
mable I/O.
The two chips which form the heart of
the F8 system are the 3850, designated
the CPU or central processing unit, and
the 3851, program storage unit or PSU.
In terms of chip area the latter device is
primarily a mask-programmed ROM,
organised as Ik bytes, which stores the
program to run the system.
Conventional bus addressing has been
avoided by moving all the memory
address registers out of the CPU and into
the PSU. The extra chip area so gained
on the CPU chip has been used to incor¬
porate a 64 byte scratchpad RAM and
two bidirectional I/O ports.
On the other hand the mating 3851
PSU device contains a number of things
which one doesn't find in a normal ROM,
such as a program counter, a stack regis¬
ter, a data counter or indirect memory
addressing register, and interrupt control
logic. Quite apart from these it also
provides two further 8-bit bidirectional
I/O ports, and a programmable timer.
Fig. 1 shows how the basic two-chip
F8 system is implemented. Fig. 2 shows
a more advanced system, which has
further features such as direct memory
addressing (DMA). This allows
peripheral devices, such as data inputs
and outputs, direct access to the com¬
puter memory. This is achieved without
any degradation in system performance,
and has the advantage of using fewer
machine cycles than would otherwise be
the case.
There are only three programmable
registers in the F8 CPU chip, apart from
the 64-byte scratchpad. The three regis¬
ters comprise an 8-bit primary accumula¬
tor, a 6-bit register used for indirect
addressing of the scratchpad (called the
ISAR), and a 5-bit status register.
MINIMUM SYSTEM F8 DEVICE FAMILY
% 2 " sh°™ ’ -ore
pad acts like a bank of 64 secondary 8-bit
accumulators. The first 11 scratchpad
bytes are directly addressable via some
of the F8 instructions, while the rest are
accessible through implied addressing
via the ISAR register. However, scratch¬
pad addresses 9-15 inclusive (decimal)
are dedicated as buffers for the PSU
addressing registers, so these will not
usually be available for other purposes.
On the software side, the F8 has a
repertoire of some 76 instruction, more
than half of which use a single byte. Of
the rest only three use 3 bytes, and the
remainder 2 bytes. This allows some
programs to be surprisingly short.
The F8 designers have achieved this
economy by relying fairly heavily on
implied addressing, where the data to be
used in executing an instruction is not
specified either directly or indirectly via
an instruction operand, but is simply
implied by the type of instruction.
In all there are some 15 accumulator
instructions, 12 branch instructions, 8
memory reference instructions, 13
address register instructions (including
jump to subroutine and return), 15
scratchpad register instructions, and 13
miscellaneous instructions.
Included in the F8 instruction set are
a number of powerful immediate instruc¬
tions, including ADD, AND, COMPARE
(2's complement subtraction), EX-OR,
LOAD and OR, together with a "call to
subroutine immediate" and a "load data
counter immediate". There is also a
"short" LOAD immediate instruction,
which is only a single byte long, and used
to load the accumulator with 4-bit data.
Readers interested in learning more
about the F8 chip-set are referred to the
previous article in this series, which
appeared in the November 1976 issue.
The Mostek F8 Evaluation Kit is avail¬
able in Australia from Namco Electronics.
Like the other evaluation kits we have
looked at, it is intended to allow potential
users to gain practical experience and
undertake simple program development
at low cost.
The kit comes well packaged in a
strong cardboard box, and comprises a
ring binder containing device specifica¬
tions and programming manuals. The
binder also includes the completed cir¬
cuit board, stapled inside a conductive
package. A separate additional program¬
mer's guide is also included.
The PCB, which can be plugged into
an edge connector, contains the CPU,
PSU and SMI (static memory interface)
86
ELECTRONICS Australia, December, 1976
GETTING INTO MICROPROCESSORS
chips, as well as Ik of RAM, and a full
duplex 20mA loop teleprinter interface.
A2MHz crystal is included, so no adjust¬
ments are required prior to switch-on.
Power requirements are 12VDC at
120mA and 5VDC at 750mA.
The Mostek debug program, called the
Designers Development Tool (DDT-1) is
resident in the PSU, and occupies the first
Ik of memory space. The Ik of RAM
appears in the second Ik of memory
space, which because of simplified
addressing logic also becomes duplica¬
ted in the succeeding 1 k bytes.
DDT-1 provides basic facilities for
development of user programs, as well
as routines for teleprinter IOT servicing.
DDT-1 allows the operator to insert a
breakpoint in his or her program, copy
a block of memory into another area,
dump memory into and load from paper
tape, execute a program starting at any
desired memory address, carry out
hexadecimal arithmetic, examine and
alter memory locations, examine and
modify the I/O ports, and to type out a
block of memory.
Namco Electronics kindly made avail¬
able to us a sample evaluation kit, which
we were able to "fire up" and try using
a Lear Siegler ADM-3 Video Terminal,
which was also on hand at the time for
review.
DDT-1 proved to be quite easy to use,
although, in common with most other
simple debug programs, it uses a carriage
return as a command terminator. This
caused no problems on the video¬
terminal, but it does tend to cause a tele¬
printer to consume a large amount of
paper. Our only real criticism is that
DDT-1 does not seem to be protected
This is the Mostek F8 evaluation kit , comprising PCB, a binder with user manuals ,
and a programmer's guide. The CPU clock is crystal controlled.
against erroneous keyboard entries.
For example, accidental type-in of the
letter O instead of a zero when feeding
in a hexadecimal address appears to
produce unpredictable results. Some¬
times part of the user's program can be
altered, which can be rather annoying! It
would be desirable for DDT-1 to be
modified so that it checks for valid
hexadecimal characters in the keyboard
ANSWER -BACK PROGRAM FOR MOSTEK F8 EVALUATION KIT
D. EDWARDS, ELECTRONICS AUSTRALIA 19/10/76
0400 20 FF INIT.LI
0402 0B LR
0403 54 LR
0404 34 DS
0405 56 LR
0406 71 LIS
0407 B6 OUTS
0408 IB El
0409 2 o 03 F3 START, PI
040C 4C LR
040D 25 OD Cl
040F 84 06 BZ
0411 28 03 5D PI
0414 90 F4 BR
0416 2A 04 23 MESSAGE, DCI
0419 70 ANSWER, CLR
041A 88
041 B 84 ED
041D 5C
041E 28 03 5D
0421 90 F7
0423 0D 47 4F
0426 20 41 57
0429 41 59 2C
042C 20 49 27
043F 4D 20 42
0432 55 53 59
0435 21 OD 00
AM
BZ
LR
PI
BR
FF /LOAD AC WITH FF
IS, A /INITIALIZE ISAR TO 3F
4, A /COPY AC INTO REG 4
4 /DECREMENT REG 4 TO FE
6, A /COPY AC INTO REG 6
H ' 1 ' /LOAD AC WITH 01
6 /TRANSFER AC TO TIMER PORT TO ENABLE EXT INT
/ENABLE I/O ROUTINES
03F3 /CALL TTYIN SUBROUTINE
AS /COPY tHAR INTO AC FROM RS
'0D' /COMPARE WITH CR
'MESSAGE' /JUMP TO MESSAGE IF CR
035D /SEND CHAR TO TTYOUT SUBROUTINE
START /LOOP BACK TO START
0423 /LOAD DC WITH MESSAGE ADDRESS
/n vat) a n
/ADD CHAR TO AC AND INC DC
START /LOOP BACK TO START
5, A /COPY CHAR INTO RS
035D /SEND CHAR TO TTYOUT SUBROUTINE
ANSWER /LOOP BACK TO ANSWER
/START OF ANSWER BUFFER
/ANSWER MUST END WITH A ZERO BYTE
Here is the author's version of our "answer-back" program, re-written for the Mostek
evaluation kit and the DDT-1 teleprinter subroutines.
input, and throws out invalid characters
with a query.
Getting to grips with programming
proved to be quite straightforward, as
Mostek have provided a fully explained
sample program. For comparison with
other systems, I have written a version of
Jim Rowe's "answer-back" program,
which is reproduced on these pages.
The first point of interest about this
program is the amount of initialization
that is required at the start, mainly to use
the IOT routines resident in DDT-1. Note
also the use of the auto-incrementing
ADD BINARY (AM) instruction together
with the branch-on-zero (BZ) instruction
in the ANSWER loop, to provide exit
from the loop at the end without the
need for a separate pointer.
Since the DDT-1 teleprinter output
routine always responds with a line feed
as well as a carriage return when a car¬
riage return is sent, no line feeds are
needed in the answer.
Overall, we found the Mostek F8 Kit
to be easy to use, and would recommend
it to those interested in using the F8 sys¬
tem. It is suitable as either an evaluation
system, or as a low cost development
tool.
The D.I.Y. kit is available for $248.34
plus tax, while the completely assembled
version sells for $300.00 plus tax.
Enquiries should be directed to Namco
Electronics, 239 Bay Street, North
Brighton, Victoria 3186, or to Namco
Electronics, 69 Archer Street, Chatswood,
NSW 2067. ®
ELECTRONICS Australia, December, 1976
7 Mcbniwiinf sa^a gf
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88
' ELECTRONICS Australia, December, 1976
GETTING INTO MICROPROCESSORS
The Sphere system
Of the many microcomputer systems based on the Motorola 6800
microprocessor chip family, perhaps those which have aroused the most
interest are the systems produced in the US by the Sphere Corporation.
No doubt this is because Sphere has integrated their basic system with
a video display and keyboard, and is selling the resultant package for
little more than the cost of a basic video terminal.
In appearance, a basic Sphere system
is very similar to a conventional video
terminal. It has a video screen and a full
ASCII-type keyboard, mounted in a well-
styled and solid terminal case. But inside
the case is a complete microcomputer as
well as the display and keyboard.
The Sphere 320 system comprises a
total of four modules: a CPU module, a
CRT interface module with video moni¬
tor assembly, a keyboard module
complete with keyboard, and serial inter¬
face module.
The CPU module provides a complete
6800 microcomputer system, on a single
PCB measuring 200 x 250mm. It includes
Ik bytes of PROM with a resident debug
and monitor program, 4k bytes of RAM
for user programs, a bidirectional 8-bit
I/O port, 2 interrupt lines, serial interface
port, and fully buffered system bus.
The CRT interface module is on a sin¬
gle PCB of the same size as the CPU. It
is designed to provide a display of 16
lines, each 32 characters long, using a
standard 5x7 dot matrix character set.
The module includes its own 512-byte
RAM for refresh servicing, so that the
CPU can operate at full speed.
The CRT module has both video and
modulated RF outputs. Its output is nor¬
mally fed directly to the inbuilt video
monitor, but can be directed to an exter¬
nal monitor or TV receiver if desired. Up
to 8 CRT modules can be operated in a
system if desired.
The keyboard module has a full ASCII
keyboard, together with the appropriate
encoding logic.
Finally the serial interface module or
"SIM" provides flexible serial interfacing
facilities, to allow the system to com¬
municate with a variety of serial
peripheral devices. These include single
and dual tape cassettes, a modem, or a
cassette and modem combination.
All of these fit into the basic Sphere
case, measuring 460 x 320 x 485mm. The
only external item is the power supply,
which is also supplied.
For those wanting a more powerful
Apart from the power supply, the Sphere
320 is fully self-contained
system than the 320, Sphere also markets
the model 340. This provides all of the
facilities of the 320, together with two
further modules: a memory board with
16k of additional memory, and a parallel
I/O module.
The 340 memory board is the same
size as the CPU and CRT modules. It has
provision for a total of 16k of dynamic
RAM devices,- and in the 340 system it
comes fully populated. Ftowever further
modules are also available, populated in
any desired 4k increment from 4k to 16k.
The parallel I/O module comes again
on a PCB measuring 200 x 250mm. It has
four PIA devices, providing a total of 64
bits of parallel I/O interfacing, together
with handshaking logic for interfacing to
peripheral devices such as a line printer
and floppy disc drive.
To mate with the more powerful 340
system, Sphere market both a line printer
unit and a dual floppy disc drive. The line
printer is a bidirectional impact printing
mosaic type, operating at a rate of 110
chars/sec and 65 lines/minute. It uses
tractor-fed paper, and prints in 80
columns.
The dual floppy disc unit uses IBM-
type initialised diskettes, and provides
storage of 256,256 bytes per diskette.
Software available for the 340 system
includes extended BA$IC, and a disc
operating system.
Literature supplied with the Sphere 320
and 340 systems is at present rather
sparse, consisting mainly of basic infor¬
mation on the 6800 microprocessor sys¬
tem. There is very little in the way of
operating or programming information
on the Sphere systems as supplied;
however we understand that this
deficiency will be rectified in the very
near future.
In view of their availability as compact,
fully assembled systems which are easily
expanded as required, both the 320 and
340 Sphere systems seem likely to be of
considerable interest in Australia.
The sole distributors for Sphere in this
country are Paradio Electronics Pty Ltd,
of 7A Burton St, Darlinghurst, NSW, 2010,
who currently have 320 systems in stock.
(JR)
ELECTRONICS Australia. December, 1976
89
<
GETTING INTO MICROPROCESSORS
Software/Firmware developments — 1
SC/MP gets Tiny-BASIC
If you've tended to scorn microcomputer systems because of the need
to program in machine or assembly language, think again. National
Semiconductor is releasing shortly a Tiny-BASIC interpreter for its
SC/MP systems. It will be sold resident in 4k-bytes of PROM, on a
PC card. Plug in the card, and you can have programs runninq in Tinv-
BASIC within the hour!
by JAMIESON ROWE
Although microcomputers haven't
been around for very long as yet, already
many of the people using them have
begun to show interest in the possibility
of programming in one of the problem-
orientated or "higher" languages like
FORTRAN or BASIC No doubt these
thoughts tend to be generated most
often when one is slogging through a
program written in hexadecimal code!
Of course in order to be able to run
programs written in a problem-
orientated language, one needs to have
them translated into language which the
computer can understand. At present this
must be done in one of two ways.
One is to use a compiler, which is itself
a computer program. When fed into the
machine, the compiler will take your
"source code" program as written, and
produce from it an "object code"
equivalent in machine language. It is this
version which you then feed into the
machine to get your program running.
The other way is td use an interpreter,
which again is also a computer program.
But unlike a compiler, an interpreter
doesn't produce a separate object code
version of your program. Instead it must
be put in the machine alongside your
program, which it interprets into
machine language and executes all at the
same time.
Which approach is used depends
mainly on whether you have a compiler
or an interpreter program available,
although an interpreter tends to be a little
more convenient because it allows faster
program development.
The problem with either approach is
that both compilers and interpreters tend
to be rather long. They are rather tricky
and tedious to write, and when written
they need quite a deal of computer
memory. The latter is especially true with
interpreters, which are loaded into
memory along with the source
program.
Because of the requirement for a fairly
large memory, until recently languages
This is the pre¬
release version of
NIBL, which was in
only 3k bytes of
PROM. The final
version is in 4k
bytes , with the PCB
having eight of the
PROMs instead of
six.
like FORTRAN and BASIC have mainly
been available only on larger com-
puters.
In the last couple of years, however,
a number of people working with various
microcomputer systems have come up
with interpreters capable of fitting into
small systems, and which provide a lim¬
ited sub-set of the full original BASIC lan¬
guage. Naturally enough the language
provided by these interpreters has
quickly become known as "Tinv-
BASIC".
Now National Semiconductor has
announced that a Tiny-BASIC interpreter
will very shortly become available for its
SC/MP microprocessor systems.
National's Australian subsidiary, NS Elec¬
tronics, expects to have it available by
late January. It will be sold as a product
package which comprises the interpreter
itself resident in 4k of PROM on a plug-in
PC card, a 2k static RAM card for the
user's source program, and a user's
manual. The complete package should
sell for around $305 plus tax, where
applicable. Those who already have
SC/MP systems with at least 2k of RAM
may also be able to buy just the
interpreter and the manual, if they wish,
by quoting the serial number of their
existing RAM board.
National has called its version of Tiny-
BASIC "NIBL", which stands for National
Industrial BASIC Language. This is meant
to emphasise that they see its applica¬
tions not only in educational and hobby
computing, but also and perhaps more
importantly in industrial control situa¬
tions.
Like most other Tiny-BASIC
interpreters, NIBL is not fast. A program
written in NIBL executes somewhere
between 1000 and 2000 times more
slowly than an equivalent program writ¬
ten in machine or assembly language. But
this can still be fast enough for most
human interfaces, and for slow real-time
control applications.
And the point is that NIBL lets you
write programs and get them running
very much more easily and quickly. It
also provides "instant" error messages
during program execution, to help you
in debugging. And it lets you execute sin¬
gle instructions in real-time conversa¬
tional mode, if you wish..
Naturally enough, NIBL doesn't
provide all of the facilities of full BASIC-
after all, it has to fit into only 4k bytes
of memory. But it does provide a very
90
ELECTRONICS Australia, December, 1976
GETTING INTO MICROPROCESSORS ■—BI" '
10 PRINT "HI* I WORK OUT FACTORIALS.”
20 PRINT "WHAT NUMBER WOULD YOU LIKE";
30 INPUT N
40 LET F* 1
50 IF N<»1 THEN GOTO 90
60 LET F=F*N
70 LET N=N - 1
80 GO TO 50
90 PRINT "ITS FACTORIAL I S"* F
91 PRINT "DO YOU WANT TO WORK OUT ANOTHER <1=YES*0=N0> >
92 INPUT A
93 IF A=1 THEN GO TO 20
100 END
> RUN
HI* I WORK OUT FACTORIALS.
WHAT NUMBER WOULD YOU LIKE? 6
ITS FACTORIAL IS 720
DO YOU WANT TO WORK OUT ANOTHER ( 1=YES* 0=N 0 ) ? 1
WHAT NUMBER WOULD YOU LIKE? 7
ITS FACTORIAL IS 5040
DO YOU WANT TO WORK OUT ANOTHER C 1=YES* 0=N0>? 0
Here are the two simple Tiny-BASIC programs which the
author wrote to try out the pre-release version of NIBL. One
works out factorials , the other is a number game.
useful subset. Here's a summary of what
you get:
Valid statement forms include INPUT
(for numbers only), LET, GO TO, GO
SUB and RETURN, IF THEN, and PRINT.
There is also a CALL statement, to allow
calling machine-language subroutines.
The latter facility is very valuable, of
course, because it will allow NIBL to be
expanded.
The final version of NIBL may also have
the ability to interpret DO . . . UNTIL sta¬
tements, if PROM space permits.
Program control statements provided
are LIST, RUN, END, and CLEAR. The first
of these may be used to list either the
whole program, or alternatively a single
line. An inbuilt editor allows lines to be
replaced, and also additional lines added
as required. All that is necessary for cor¬
rect execution is that lines are numbered
consecutively between 1 and 32, 767.
If statement lines begin with a number,
NIBL stores them away as a program for
deferred execution. If a statement is not
numbered, NIBL executes it immediately
upon entry (following the user terminat¬
ing the line with a carriage return).
NIBL is only capable of performing
integer arithmetic, on numbers within the
range from —32,768 to +32,767. It
provides the four basic arithmetic func¬
tions, represented by the symbols + ,-,*
and /, together with the logic operators
AND, OR and NOT, and a 16-bit random
number generator function called by the
label RND. Constants may be expressed
in either decimal or hexadecimal.
Up to 26 variables may be used in a
NIBL program, using single alphabetic
characters as labels (A-Z inclusive).
Parenthesis is permitted, and subroutines
may be nested to 16 levels.
All of the normal relational operators
are provided, including equals, greater
than, less than, greater than or equals,
less than or equals, and not equal to.
NIBL also provides an operator of
indirection, symbolised by the "at" or
10 PRINT "HI ! I WILL THINK OF A NUMBER BETWEEN 0 AND 255*
20 PRINT "WHEN I HAVE* TRY TO GUESS ITS VALUE. (I WILL HELP)"
30 LET B= 1
40 LET A= §B
50 PRINT "OK* I HAVE A NUMBER"
60 PRINT "WHAT IS YOUR GUESS";
70 INPUT C
80 IF C= A THEN GOTO 140
90 IF C> A THEN GOTO 120
100 PRINT "TOO SMALL. NEXT GUESS";
1 10 GO TO 70 •
120 PRINT "TOO BIG. NEXT GUESS";
130 GO TO 70
140 PRINT "YOU GUESSED IT!!! LET'S PLAY AGAIN.
150 LET B=B+ 1
160 GO TO 40
170 END
> RUN
HI! I WILL THINK OF A NUMBER BETWEEN 0 AND 255.
WHEN I HAVE* TRY TO GUESS ITS VALUE. (I WILL HELP)
OK* I HAVE A NUMBER
WHAT IS YOUR GUESS? 200
TOO BIG. NEXT GUESS? 180
TOO SMALL. NEXT GUESS? 196
YOU GUESSED IT!!! LET'S PLAY AGAIN.
OK* I HAVE A NUMBER
WHAT IS YOUR GUESS? 128
TOO BIG. NEXT GUESS? 64
TOO BIG. NEXT GUESS? 32
TOO BIG. NEXT GUESS? 0
TOO SMALL. NEXT GUESS? 16
YOU GUESSED IT!!! LET'S PLAY AGAIN.
OK* I HAVE A NUMBER
WHAT IS YOUR GUESS? 128
TOO BIG. NEXT GUESS? 0
TOO SMALL. NEXT GUESS? 64
TOO BIG. NEXT GUESS? 32
TOO SMALL. NEXT GUESS? 45
TOO SMALL. NEXT GUESS? 56
TOO BIG. NEXT GUESS? 60
TOO BIG. NEXT GUESS? 50
TOO SMALL. NEXT GUESS? 54
YOU GUESSED IT!!! LET'S PLAY AGAIN.
OK* I HAVE A NUMBER
WHAT IS YOUR GUESS?
! 7 AT 70
sign. When placed immediately
preceding a variable this causes the varia¬
ble to be interpreted as a decimal
address in SC/MP memory space. If A is
a variable with value 256, the statement
LET B = @A gives variable B the value
equal to the data byte in decimal
memory location 256.
What is NIBL like in practice? Well, at
the time of writing the final version was
not yet available in Australia, but thanks
to NS Electronics I was able to try an
earlier pre-release version. This was in
only 3k of PROMs, and didn't have some
of the features which will be in the full
4k version-like the RND function or the
logic functions, or the CALL statement.
However it was certainly very interes¬
ting to try the smaller version out, with
one of the SC/MP LCDS systems. Even
though its facilities were rather limited,
it was still very nice to be programming
at a higher level of abstraction and be
able to make corrections on-line.
In fact after having got a couple of sim¬
ple programs up and running, it was with
surprise that I noticed the time: less than
an hour after the NIBL card had been
plugged in and the system turned on!
As the two programs might be of
interest to readers, I have reproduced
them on these pages. In each case the
program itself is listed first, followed by
a sample of the execution.
As you can see, the first program is a
very simple one which calculates the fac¬
torial of a number fed in from the
keyboard. It prompts the user for a num¬
ber, prints out the answer and then asks
if the user wishes to work out another.
A negative reply causes it to halt.
Incidentally, this little program soon
comes up against the inability of NIBL to
cope with numbers greater than 32,767.
In fact the largest number it can find the
factorial for is 7; 8 causes overflow.
The longer program is a simple num¬
ber guessing game. As the pre-release
version of NIBL didn't have the RND
function, I had to use the indirect opera¬
tor to generate pseudo-random numbers
by fetching instruction bytes from NIBL's
own PROMs! As you can see, this
worked fairly well.
The program can be quite good fun,
giving you a taste of the appeal in com¬
puter games.
Of course with the final version of
NIBL, it will be possible to run games like
this which will be rather more satisfying,
using the RND function to generate less
predictable numbers. In fact quite a few
games have been written in Tiny-BASIC,
and should be capable of being run with
NIBL.
In short, NIBL seems to be very good
news for SC/MP users.
You'll be able to order NIBL from NS
distributors throughout Australia. For
further information, contact NS Elec¬
tronics at either Cnr. Stud Road and
Mountain Hwy, Bayswater, Victoria 3153,
or 2-4 William Street, Brookvale, NSW
2100. ®
ELECTRONICS Australia, December, 1976
91
GETTING INTO MICROPROCESSORS
Software/ Firmware development — 2
A Text Editor for SC/M P
Here is a symbolic text editor program which the author has written
for National Semiconductors SC/MP low cost development system.
It provides all the basic text editing functions to let you prepare
programs for assemblers, compilers, etc. You will be able to buy it
resident in 1 k bytes of PROM and ready to go, or, alternatively, it can
be fed into your system via tape or cassette, and run in RAM.
by JAMIESON ROWE
If you've ever tried punching up a
paper tape of a program in assembly or
problem-orientated language using a
teleprinter on "local", you'll know just
how frustrating it can be. Even if you are
extremely careful it seems to be impos¬
sible not to make a few errors, and
Murphy's Law always seems to ensure
that you rarely discover these until you
have typed in at least three more lines!
Of course if you realise that you made
an error immediately after having done
it, you can use the back-space facility and
delete the wrong character(s) with the
rubout key. But if you don't discover an
error until later on, you are forced to
either perform cut-and-paste surgery on
the tape, or try stop-and-go editing of the
tape while punching a new "clean" ver¬
sion.
Preparing long problems in this way
can be very tedious and time consuming.
Small wonder, then, that the people
working on minicomputers and larger
machines have for years been using the
computer itself to make the job easier
and faster. This is done by using a soft¬
ware utility program known as a sym¬
bolic text editor.
Using such a program, you type your
own program text into a section of the
computer's memory which is set aside as
the "buffer". Then with the text in the
buffer, the editor lets you change lines,
delete lines, insert extra lines at any
desired point, inspect lines or groups of
lines, and finally either type out a listing
or punch out a clean tape (or both).
In short, a text editor program can be
a very useful item of software, and it is
well worth having one even on small
microcomputer systems. The only
trouble is that not too many microcom¬
puters have been provided with editor
programs as yet, particularly the systems
based on the more recent microproces¬
sor chips.
To help alleviate this situation, I have
written a text editor program for the
National Semiconductor SC/MP lowcost
development system, as described in our
October issue. I chose this system
because at present the SC/MP chip and
its systems appear to be growing fastest
in popularity, particularly in the hobby
area.
The editor program itself is written in
SC/MP machine language, and occupies
864 byte$ of memory. It uses the 256-byte
RAM in the LCDS system base as a stack
and line address buffer, but can use RAM
memory at any other location in SC/MP
memory space for its text buffer. The lar¬
ger the available RAM, the more text the
editor can handle at one time.
I have arranged for the editor to be
available from NS Electronics distribu¬
tors, written into a pair of MM5204
512-byte PROMs. With the PROMs plug¬
ged into the correct locations on a
.SC/MP ROM card which is programmed
for the appropriate address range (hex.
3000-3FFF), you will then have the editor
permanently resident in your system, and
available at any time merely by calling it
at its starting address (hex. 3C00).
Alternatively, you can run the editor in
RAM memory, loading it in each time you
need it by means of a punched paper
tape or cassette. I am reproducing a full
hexadecimal listing of the program on
these pages, to allow you to do this if you
wish. The four-digit numbers at the start
of each line are addresses; as you can see
the program runs from 3C00 to 3F5F,
inclusive.
SC/MP SYMBOLIC EDITOR PROGRAM.
WRITTEN BY J.ROWE* ELECTRONICS AUSTRALIA
FOR SC/MP L.C.D. S. SYSTEMS
BASIC COMMANDS AND THEIR FUNCTIONS:
(THE CLOSING BRACKET ”)” SYMBOLISES A CARRIAGE RETURN)
COMMAND
FUNCTION
A)
R)
L)
MC)
MI )
MD)
K)
P)
B)
ML) * Mj
> M* N C)
NL)
APPEND LINES TO BUFFER
READ TAPE INTO BUFFER
LIST ALL LINES* OR LINE M* OR LINES M-N
CHANGE LINE M* OR LINES M-N
INSERT LINE OR LINES BEFORE LINE M
DELETE LI^JE M* OR LINES M-N
KILL TEXT IN BUFFER
PUNCH ALL LINES* LINE M* OR LINES M-N
AS FOR PUNCH* BUT PUNCHES A BELL CHAR
AT END OF TEXT
EDITOR PRINTS NUMBER OF LINES CURRENTLY
HELD IN TEXT BUFFER* IN DECIMAL
WHEN IN TEXT MODE* RETURNS EDITOR TO
COMMAND MODE
<M AND , N REPRESENT DECIMAL LINE NUMBERS)
* M*ND)
MP)
MB)
M*NP)
M* NB)
/
BELL
thKi baSIC command set of the editor , showing the various command lexers
acts ^as^ backspace^ ^ ^ ^ functions‘ ln text mode' a Percent sign
iNoie tnat it you do elect to run the edi¬
tor in RAM, you will need at least one
2k-byte RAM card. This will give you Ik
of RAM left for the text buffer— enough
for small text slabs, but barely good
enough for serious work. With the editor
in PROMs, even a single RAM card gives
you a full 2k for the text buffer, which
is very much more practical.
When the editor is called, it announces
itself and then asks you to give the avail¬
able text buffer range in memory. This
must be supplied as two hexadecimal
numbers, separated by a non-hex
character such as a space or hyphen.
Leading zeroes are not required, but the
second number must end with a carriage
return.
The editor then enters its command
mode, signalling this by ringing the bell.
The user may then type in a command
letter, followed by a carriage return. If
text is to be fed in via the keyboard, the
command letter "A" is appropriate, while
"R" tells the editor to read in a previously
punched tape via the reader.
92
ELECTRONICS Australia, December, 1976
Intersil
ICL8211
ICL8212
3C00 04 C4 77 36 C4 FF 32 C4 7B 37 C4 16 33 3F 3F 07
3C10 C4 4F 33 3F C6 01 CA FI C6 01 CA EF 3F C6 01 CA
3C20 EF C6 01 CA ED C4 00 CA F9 C2 F0 CA F8 C2 EF CA
3C30 F7 C4 7 A 37 C4 El 33 C4 07 3F C4 0D 3F C4 0A 3F
3C40 C4 00 CA F 4 CA F3 CA F2 C4 7A 37 C4 90 CA F 1 33
3C50 3F D4 7F 01 C4 3F 35 C4 2B 31 C5 03 98 3B 60 9C
3C60 F9 Cl FE CA F6 Cl FF 31 C2 F6 35 C2 F9 03 FA F3
3C70 94 02 90 12 C2 F9 03 FA F2 94 02 90 09 C2 F2 98
3C80 10 03 FA F3 94 0B C4 7A 37 C4 El 33 C4 3F 3F 90
3C90 A9 3F D4 7F E4 0D 9C EE 3D 40 D4 70 E4 30 98 19
3CA0 40 E4 2F 9C 09 C4 3E 35 C4 B2 31 3D 90 8C 40 E4
3CB0 2C 9C D3 C4 01 CA F4 90 8F 40 D4 0F CA F5 C2 F4
3CC0 9C 04 C2 F3 90 02 C2 F2 02 01 40 70 01 70 70 01
3CD0 40 70 F2 F5 01 C2 F4 9C 05 40 CA F3 90 D9 40 CA
3CE0 F2 90 D4 35 CA F6 31 CA F5 C2 F7 CA E9 C2 F8 CA
3CF0 EA C2 FI E4 84 98 09 C4 7A 37 C4 El 33 C4 0A 3F
3D00 C4 7 A 37 C2 FI 33 C2 EE 02 F4 01 EJ2 F8 98 53 C2
3D 1 0 F8 35 C2 F7 31 3F D4 7F 01 40 E4 0A 98 ID 40 E4
3D20 07 98 3F 40 E4 25 9C 04 C5 FF 90 0F 40 98 0C E4
• 3D30 7F 98 08 40 E4 0D 98 01 40 CD 01 C4 77 35 CA F8
3D40 C2 F3 02 F2 F3 31 CA F7 40 E4 0D 9C B6 C2 E9 C9
3D50 00 C2 EA C9 01 C2 F9 E4 74 98 07 C2 F6 35 C2 F5
3D60 31 3D C4 3C 35 C4 30 31 C4 90 CA FI 3D 08 08 08
3D70 C4 80 90 02 C4 01 CA F 1 C2 F3 9C 0A C4 01 CA F3
3D80 C2 F9 CA F2 90 08 C2 F2 9C 04 C2 F3 CA F2 C4 El
3D90 33 C4 0A 3F C2 FI 98 15 C4 7A 37 C4 88 33 3F C4
3DA0 El 33 C4 C0 CA F6 C4 00 3F AA F6 9C F9 C4 77 35
3DB0 C2 F3 02 F2 F3 31 Cl 00 CA F6 Cl 01 35 C2 F6 31
3DC0 C5 0 1 98 03 3F 90 F9 C4 0D 3F C4 0A 3F C2’ F3 E2
3DD0 F2 98 04 AA F3 90 D6 C2 FI 98 1A 94 03 C4 07 3F
3DE0 C4 C0 CA F6 C4 00 3F AA F6 9C F9 C4 7A 37 C4 88
3DF0 33 3F C4 El 33 C4 3C 35 C4 39 31 3D 08 08 08 08
3E00 C2 F2 9C 06 C2 F3 98 35 CA F2 BA F3 C2 F2 E2 F9
3E10 98 20 AA F3 AA F2 C4 77 35 C2 F2 02 F2 F2 31 C4
3E20 77 37 C2 F3 02 F2 F3 33 Cl 00 CB 00 Cl 01 CB 01
3E30 90 DA C2 F3 CA F9 C4 3C 35 C4 30 31 3D C4 3C 35
3E40 C4 83 31 3D C2 F3 98 F5 C2 F2 9C FI C4 77 35 C2
3E50 F3 e(2 F2 F3 31 Cl 00 CA EB C 1 0 1 CA EC C4 3C 35
3E60 C4 E2 31 3D C2 F9 CA F2 AA F9 C4 77 35 C2 F2 02
3E70 F2 F2 31 Cl 00 C9 02 Cl 01 C9 03 C2 F2 E2 F3 98
3E80 04 BA F2 90 E5 C2 EB C9 02 C2 EC C9 03 AA F3 90
3E90 BB C2 F2 9C 06 C2 F3 98 A4 CA F2 C4 3C 35 C4 E2
3EA0 31 3D C2 F3 E2 F2 98 04 AA F3 90 EF C4 3C 35 C4
3EB0 30 31 3D C4 00 CA F6 CA F5 CA F4 C2 F9 02 F4 9C
3EC0 94 05 C2 F9 01 90 03 01 AA F6 40 02 F4 F6 94 02
3ED0 90 05 01 AA F5 90 F3 40 02 F4 FF 94 02 90 05 01
3EE0 AA F4 90 F3 C4 7A 37 C4 El 33 C4 3D 3F C2 F6 98
3EF0 03 C4 31 3F C2 F5 98 03 DC 30 3F C2 F4 DC 30 3F
3F00 C4 3C 35 C4 39 31 3D 0D 0A 45 44 49 54 4F 52 20
3F10 52 45 41 44 59 2E 0D 0A 47 49 56 45 20 42 55 46
3F20 46 45 52 20 52 41 4E 47 45 3A 00 4 1 3F 4A 52 3F
3F30 46 4C 3D 75 43 3E 90 49 3E 43 44 3D FF 4B 3C 24
3F40 50 3D 73 42 3D 6F 00 C4 84 90 02 C4 90 CA FI C2
3F50 F9 CA F3 AA F3 C4 3C 35 C4 E2 31 3D AA F9 90 EF
Use this complete hexadecimal listing of the program if you
wish to prepare a paper tape or cassette to run the editor in
RAM , or if you are able to burn your own PROMs .
Once the text is in the buffer, you can edit it using the com¬
mands shown in the table. Note that the L, C, I, D, P and B
commands may all have arguments, to specify individual lines
or a group of lines. In fact the I command must have one
argument, to indicate where the insertion is to take place.
The argument number pr numbers must precede the com¬
mand letter. Thus to list lines 12 to 15, for example, you simply
type 12, 15L followed by a carriage return.
To change a line, say line 34, you simply type 34C, a carriage
return, and then type in the new line text. Similarly to insert
a new line or lines before an existing line, say line 17, type
171 followed by a carriage return and then type in the extra
lines. To delete lines, say lines 20, 21 and 22, type 20, 22D
and then a carriage return.
A single argument implies that the command should affect
only the one line. Two arguments imply that the command
should affect all lines between the two corresponding lines,
inclusively. Thus 15, 20C implies that six new lines are to be
fed in, replacing the existing lines 15, 16, 17, 18, 19 and 20.
' (Continued on page 133)
1
MICROPOWER VOLTAGE DETECTOR/
INDICATOR/VOLTAGE REGULATOR/
PROGRAMMABLE ZENER
FEATURES
• High accuracy voltage sensing and generation: internal
reference 1.15 volts typical
• Low sensitivity to supply voltage and temperature varia¬
tions
• Wide supply voltage range: Typ. 1 .8 to 30 volts
• Essentially constant supply current over full supply
voltage range
• Easy to set hysteresis voltage range
• Defined output current limit - ICL8211
High output current capability - ICL8212
• Innumerable useful applications including:
1 . Low voltage sensor/indicator
2. High voltage sensor/indicator
3. Non volatile out-of-voltage range sensor/indicator
4. Programmable voltage reference or zener diode
5. Series or shunt power supply regulatoi
6. Fixed value constant current source
• Low cost
CONNECTION DIAGRAM
N/C [T
HYSTERIS1S |T
THRESHOLD [T
OUTPUT [T
~8~1 V*
T) N/C
T| N/C
T| v.
8 LEAD PLASTIC MINI DIP
HYSTERESIS
Available from
R & D ELECTRONICS PTY. LTD.
23 Burwood Road. Burwood. Vic.
Tel. 288 8262, 288 8232.
MELBOURNE
Total Electronics.
239 Bay Street
NTH BRIGHTON VIC
Phone 96 2891
SYDNEY
Total Electronics.
35 Aitchmson St.
ST LEONARDS NSW
Phone 439 6722
BRISBANE
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Kingsford Smith Dr.
EAGLE FARM OLD
Phone: 268 5766
ADELAIDE
Total Electronics.
709 Port Road.
WOODVILL SA
Phone: 45 1129
ELECTRONICS Australia. December, 1976
93
SPECIAL PURCHASE-new garrard
RECORD CHANGERS AT A FRACTION OF LIST PRICE
GARRARD ZERO 100
TRANSCRIPTION CHANGER
$80.00
(Normal lecommended retail price $198.00).
Supplied with Pickering Magnetic Cartridges
with Diamond Stylus.
Post & Packing (Reg. post) N S W. $5.50, Vic. S.A.
& Qld. $6.75, Tas. $6.50, W.A. & N T. $8.75.
GARRARD M.82 $57.00
TRANSCRIPTION CHANGER
Recommended retail price $120.00
Supplied with Pickering Magnetic Cartridge with
Diamond Stylus. Post & packing (Reg. post)
N S W. $3.60, Vic., S.A., Qld. $4.74, Tas. $5.50
W.A. & N T. $6.75.
GARRARD SL 95B
TRANSCRIPTION CHANGER
$69.00
Recommended retail price $175.
Supplied with Pickering Magnetic Cartridge with
Diamond Stylus. Post & packaging same as Zero
100.
GARRARD 6-400
CHANGER
$28.50
Recommended retail price $48.00
Supplied with high quality Garrard /Sonatone
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GARRARD CC10A
RECORD CHANGER
$14.75
Fitted with a Sonatone Garrard Ceramic Car¬
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RECORD PLAYER
CARTRIDGE AND
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$9.50
BASE & PERSPEX COVERS AVAILABLE IN TEAK & WALNUT FINISH
FOR ILLUSTRATIONS & SPECIFICATIONS OF GARRARD CHANGERS SEE OCT OR NOV ISSUE OF ELECTRONICS AUSTRAI IA
GENESOIMICS 10
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PORTABLE
Thissensitive & selective pocket radio using 6 transis-
tors & 4 diodes is suitable for most local & country
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A three way Speaker System with a
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PHONES 798 7145, 798 6507
94
ELECTRONICS Australia, December, 1976
Classical
Recordings
Reviewed by Julian Russell
Wagner — Tristan and Iso/da: "glorious”
WAGNER-Tristan and Isolda.
Complete Music Drama. Wolfgang
Windgassen (Tristan); Martti Talvela
(King Mark); Birgit Nillson Isolda;
Eberhard Waechter (Kurvenal);
Claude Heater (Melot); Christa
Ludwig (Brangane); Erwin Wohlfahrt
(Shepherd) and others with the
Chorus and Orchestra of the
Bayreuther Festspiele conducted by
Karl Bohm. DGG Stereo 2720 057.
This was the third of the three great
Tristan recordings issued during the
middle 1960s. The conductors of the
other two were Furtwangler (HMV) and
Solti (DECCA). The singers and orches¬
tras varied, though it would be profitless
in the space available to compare the pro¬
ductions singer by singer and note by note
except in rare, significant instances.
But let me say at the outset that I have
had— and loved despite their differ¬
ences— the other two for many years, and
that I acquired the Bohm only last month
when I listened to it for the first time. I
confess right away that I fell for it hook,
line and sinker— as the saying goes.
true there are slight details in the per¬
formances of the other two that I prefer,
but judging Bohm's production as a
whole I consider it the best. It was
recorded live at the 1966 Bayreuth Fes¬
tival where the inspired placing of the
microphones recapture, in all but a few
bars, the glorious acoustics of the
Bayreuth Festspielhau? to give us a
peerless balance between voices and
orchestra. It may be recalled that in the
Furtwangler, in which the superb Flag-
stand was the Isolda, it was necessary for
Schwartzkopf to stand by to take high
notes that were then outside the aging
Flagstad's range.
In Bohm's recording the Isolda is Birgit
Nillson who fills the role in & perform¬
ance that will live long in glory. I have
heard her in the part many, many times,
both live and on disc, but in this perform¬
ance she surpasses anything she has ever
done before. Apart from the splendour
of her voice she is the living embodiment
of the character, mature yet reckless in
her anger, meltingly beautiful in her love
scenes, yet at all times refined in her sen¬
suality. The same might be said of
Bohm's control over the whole produc¬
tion.
Despite the live recording there is a
micro-minimum of extraneous stage
sounds and the audience behaves with
unsurpassable decorum. I couldn't even
hear the softest cough. Except for the
perfection of the sound, which wears
amazingly well, the performance might
have been recorded in an empty hall.
I could go on for pages describing
Bohm's total commitment to the won¬
derful score, not the least feature of
which is his respect for the short silences.
If Nillson starts a trifle unsteadily it takes
her practically no time at all to recover
and give a performance which I consider
quite peerless by present day standards.
The same might be said of Christa
Ludwig's Brangane, though here you
have to wait till the second act to hear
her at her best. This is not to say that she
hasn't some transcendentally lovely
moments in the first act, too.
Wolfgang Windgassen is a noble Tris¬
tan, his full, rich tenor entirely free from
any hint of a Bayreuth "bark." His
demeanour, even when discovered in
guilt, remains courtly, his passion in the
tumultuous love scenes ardent without
any forcing of his voice.
Eberhart Waechter's Kurvenall is not
the boisterous soldier depicted in so
many other readings of this important
part. Waechter's is dominated by his love
and respect for his master for whom he
willingly lays down his life and takes
purely human revenge on Melot, his
master's betrayer. You feel that he thinks
that Tristan at his most guilty in his
betrayal of King Mark can do no wrong
and that there only remains Kurvenal's
loving protection to prevent his being
found out.
Then among the chief characters is
Martti Talvela's knightly King Mark, his
bass so enchanting to hear that all sense
of boredom with his moralising in Act 2
is completely forgotten. Special mention
must be made of Erwin Wohlfahrt's
Shepherd. And in his contribution I might
mention that in Act 3 Bohm uses the
Bayreuth alpenhorn, instead of the
previously used cor anglais, to express by
the clarion jubilation of its tone Isolda's
return to her dying Tristan.
While it is true, from a realistic point
of view, that it would have been
extremely unlikely that the Shepherd
would have had two different instru¬
ments to express the difference between
despair at the sight of an empty sea and
joy at the appearance of Isolda's ship,
one is never concerned with realism in
Wagner's wholly engrossing score. I per¬
sonally consider it to be one of the grea¬
test achievements of the human mind.
Bohm's reading is at once miraculously
sympathetic to the singers but utterly
authoritative in his command of his
splendid cast. To me the Bayreuth
Orchestra has never sounded better,
though I must mention that the only
disappointment I felt was in the recor¬
ding (a little too faint) of the hunting
horns, played out of sight at the opening
of Act 2. There are also one or two
moments when the voices have a slight
tendency to dominate the ensemble in
a way not uncharacteristic of DGG's
operatic recordings. But these are details
I feel churlish about pointing out , so
great was my enjoyment of the whole
production. Parts of the final liebestod
provide readily available instances to
check on this favouring of the voice.
One other point of interest. In the Solti
version one side is given to the conduc¬
tor rehearsing the performers. The same
occurs in the Bohm recording but here
the conductor's German remarks are
translated - or rather summarised into
English so that anyone can follow Bohm's
remarks with the greatest ease. All three
sets I have mentioned in this review are
superb, but to me the Bohm is the finest
of all.
* * *
WAGNER - Tristan and Isolda excerpts
by the same cast as above. DGG Dol-
byed Stereo Cassette 3306 001.
This cassette is a neatly cobbled
collection of excerpts from the complete
set reviewed above. During its 51
minutes of playing time it gets in the
Prelude to Act 1 and part of the second
act love duet starting with the relaxed
sequence and finishing at a spot that
doesn't spill too much blood during the
surgery. These are on the first side.
Side Two continues the Love Duet and
runs it complete till the entrance of King
Mark and the restatement of the Hunting
Horn theme. Then comes the Prelude to
Act 3, and then the Shepherd's long cor
anglais solo, followed by Tristan's last
outburst when Isolda's ship is sighted.
The cassette finishes with the Liebestod
which ends the opera.
The Dolbyed sound is excellent, so
good that only the keenest ear might tell
the difference between it and a disc if the
equipment were out of sight — even then,
most would not be prepared to bet on
it. The whole cassette might be regarded
as an aperitif that would send the average
Tristan lover rushing to the nearest music
store to get a complete set. I have only
one tiny quibble - the brief annotations
are in untranslated German which might
cause some inconvenience to those
unfamiliar with both the language and
the whole work.
ELECTRONICS Australia, December, 1976
95
CONVERT YOUR VIDEO GAME TO
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96
ELECTRONICS Australia, December, 1976
SAINT-SAENS - Symphony No. 3 in C
Minor (Organ Symphony) with Gas¬
ton Litaize at the organ and the
Chicago Symphony Orchestra con¬
ducted by Daniel Barenboim. DGG
Stereo Dolbyed Cassette 3300 619.
The folder on this cassette contains a
bit more information that is usual for
similar productions. Most of this is his¬
torical rather than analytical, but does
include the fact that the organ part,
played by Gaston Litaize on the Chartres
Cathedral updated instrument, was
superimposed on the orchestral record¬
ing. This has been done sa skilfully that
without pre-knowledge few would guess
the tape had been manipulated. Indeed
it makes for better balance between
organ and orchestra than might other¬
wise have been achieved, however much
purists might decry such "faking."
The sound is superbly spacious with a
copious amount of detail and a wide
range of dynamics used by Barenboim to
produce highly sensitive inflections. His
tempos are to me just right, without any
of the freakishness in which he some¬
times indulges elsewhere. His reading
lends the work more stature then it
usually receives. Moreover the Chicago's
a grand orchestra nowadays and this
performance— and recording— might well
provide a thrill even for those who follow
the fashionable trend to disparage
everything Saint-Saens ever wrote. True
some of his large output might well be
disregarded, but by no means all. The
very enthusiastic support he received
from his contemporary Gounod might
explain today's prejudices among the
illuminati.
There is commendable restraint in the
spirited first movement, a virile Scherzo
beautifully pointed by the orchestra, and
a Finale full of splendidly controlled dif¬
fering moods. The range of frequencies
is more than satisfactory. In the last bar
of the Finale the organ continues to linger
in the air for a moment after the orchestra
stops but whether this is intentional or
not I do not know. In any case I found
the whole production most enjoyable.
STRAVINSKY - Le Sacre du Printemps.
Complete ballet. The London
Symphony Orchestra conducted by
Colin Davis. Philips Dolbyed Stereo
Cassette 7317 119.
This is another 10-year-old original
sucessfully transferred to a Dolbyed cas¬
sette. Yet the sound remains good and
the amount of detail that emerges from
the complex score most commendable.
Although there have since been better
recordings, at any rate on disc, than this
reissue there are two features of Davis'
interpretation that can immediately be
appreciated. The first is Davis' obvious
pagan delight in the work's stamping
primitive rhythms; the other his lyrical
treatment of much quieter reaches of the
score, for example the openings to
Scenes 1 and 2, though they do lack a
sense of mystery. And if he spares us
some of the more brutal aspects of the
work his contrasting lyricism is quite
without sentimentality. To put it another
way, the women are unmistakably
women, albeit primitive ones, and the
men their warriors and masters.
From this you might well gather that
Davis' is a pretty straightforward reading
eminently suitable for an accom¬
paniment to a stage spectacle, especially
as choreographed by the fabled Nijinsky.
And it must be remembered that the
work was designed by Stravinsky for the
theatre, though nowadays it is more
often heard at a symphony concert than
combined with dancing.
Like most of the great Stravinsky
ballets it loses nothing as a piece of music
— and a very influential piece at that. Lis¬
tening to it I had the feeling that Davis
was basing his reading on those recorded
by Stravinsky himself, except that Davis'
is better. The composer was never one
to indulge himself or his audiences in
extravagant espressimos.
Davis is slightly more relenting though
never exaggeratedly so. He remains con¬
sistently exuberant. Le Sacre obviously
excites Davis very much, and this he
communicates to the listener without
chasing too much subtlety. I think that if
an entrepreneur had the idea of reviving
the work in its original ballet form, Davis
is the conductor he should choose. His
reading is fresh and youthful and, even
though he is now a little more than ten
years older than he was when he made
the original recording, I imagine it would
remain so. As to acquiring it, my advice
is to wait until some more alternatives
appear on the market, though this is not
to say that you might not even then
prefer the Davis interpretation.
RIMSKY-KORSAKOV - May Night.
Complete Opera. Alexei Krivchenja
(Mayor); Konstantin Lisovsky
(Levko); Ljudmilla Sapegena (Hanna);
Anna Matjushina (Sister-in-law); with
the Chorus and Orchestra of the Mos¬
cow Radio conducted by Valdimir
Fedoseyev. DGG Stereo SLP
2709 063.
So far as I can trace, this is the first
complete recording of Rimsky's early but
tuneful opera. Although the material
sounds a trifle thin when compared to
such more mature compositions as Le
Coq d'Or, and lacks some of the latter's
exquisite glitter, it nevertheless displays
all the early brilliance of Rimsky's scor¬
ing. Like most Russian operas it contains
many genuine folk songs and other
melodies that sound very much like
them.
One has come to always expect
superb chorus work in Russian Operas
and you have it here, too. The orchestra
is also in top form and immediately
responsive to the conductor.
Levko, tenor Konstantin Lisovsky, is a
reliable performer, a little throaty at times
but always secure in-pitch throughout his
range. Balance between the singers and
orchestra is never a problem. And
Lisovsky, despite his very forward
characteristically Russian production,
can still make his voice very expressive
in lyrical passages. All the other men are
good.
But as in most Eastern European
productions the women are awfully shrill
in voice, in quality and with a wobble that
Fred Astaire might easily fit a step dance
to. Another oddity - the libretto is by
Rimsky himself and contains, at any rate
in translation, such poetic gems as "The
water is lapping in the lake as quietly as
a child in its cradle." And although the
diction is clear it is difficult to follow the
translation.
Because May Night is a comparatively
early work, it is not surprising to find
influences of the styles of previous
operatic composers. There is, for
instance, more than a hint at times of
Weber's Oberon and some tunes of
Rimsky's own that he himself used in
later works. Indeed some of them will
tantalise you to identify. But in its favour,
the work, though early, has a very profes¬
sional polish, the sound is fine, and the
chorus sings as well as one has come to
expect from that part of the world. The
action is a fairy story that tells of a spring
nightin the Ukraine - during the last cen¬
tury, of course. ®
SAY THANK YOU
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Melbourne— 88 5282.
ELECTRONICS Australia, December. 1976
97
Noil rated!
In US by “Consumer _
Report” m
00IKVU5
Thoroughly recommended
in Australia by a major
electronics publication.
Electronic Concepts Pty. Ltd.
is proud to introduce
the exclusive Corvus 500.
Wtih MOSTEK* single chip technology, the
new Corvus 500 is the first non-Hewlett-
Packard calculator with Reverse Polish
Notation. 10 addressable memories, 4 level
roll down stack to be introduced. If you
compare the Corvus 500 feature by feature
with the HP45, you will find striking
similarities. There are also some important
differences.
'MOSTEK is one of America’s advanced LSI
(Large Scale Integration) chip manufacturers.
Corvus HP
500 45
RPN (Reverse Polish Notation) Yes Yes
Memory Store and Recall 10 Registers Yes Yes
4 Level Stack. Rotate Stack Yes Yps
IO MEMORY EXCHANGE WITH X Yes No
Log. LN Yes Yes
Trig (Sine. Cosine. Tangent. INV) Yes Yes
HYPERBOLIC (SINK COSINH
TANH. INV) yes No
HYPERBOLIC RECTANGULAR Yes No
y . e. 10. V“x7 1/x. x!. x«— y.
it. CHS Yes Yes
Vy through INVERSE Yes No
GRADIANS mo Y~
DEGREE 'RADIAN CONVERSION Yes No
Degree Radian Mode Selection Yes Yes
DEC DEG MIN SEC No Y«
Polar to Rectangular Conversion Yes Yes
Recall Last X Yes Yes
Scientific Notation. Fixed and Floating Yes Yes
Fixed Decimal Point Option (0 9) Yes Yes
DIGIT ACCURACY J2 10
DISPLAY OF DIGITS t o io
%. A S Yes Yes
GROSS PROFIT MARGIN % Yes No
Mean and Standard Deviation Yes Yes
1 +. 2- Yes Yes
Product Memories Yes Yes
C F DIRECT CONVERSION Yes No
F.C DIRECT CONVERSION Y« No
UT GAL DIRECT CONVERSION Yes No
KG LB. DIRECT CONVERSION Yes No
GAL-LIT. DIRECT CONVERSION Y« No -
LB-KG. DIRECT CONVERSION yS No
CM INCH DIRECT CONVERSION Y« No
INCH-CM DIRECT CONVERSION Y« No
As you can see, the Corvus 500 is a lot more
calculator for $95.
Price $95.00
Mail charge $2.50
Sales Tax exempt $85.00
For sales tax exempt purchases, please supply
number or certificate.
We have listed some of the many features, but
let s amplify on some highlights:
1. RPN (Reverse Polish Notation)
“COMPUTER LOGIC” and 4 LEVEL STACK.
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Your problem is solved the way it is
written, left to right sequence, eliminating
restructuring, unnecessary keystrokes, and
the handicap of having to write down
intermediate solutions. And all information is
at your disposal — just roll the stack (R) to any '
intermediate information desired. You arrive
at your solution faster, more simply and,
therefore, more accurately.
Perhaps at this point we should address
ourselves to the controversy between
algebraic entry and RPN. One question we
must ask is why proponents of algebraic entry
always use an example of sum of products
and never an example of product of sums:
(2+3) x (4+5) =
Algebraic2 + 3 = MS5 + 4 = XMR =
TOTAL 12 keystrokes (SR51, add 2 more
keystrokes)
RPN: 2Enter3 + 4Enter5+x
TOTAL 9 keystrokes
2. THE CORVUS 500 and HP-45 HAVE 10
ADDRESSABLE MEMORY REGISTERS 4
LEVEL OPERATIONAL STACK, and a
‘‘LAST X" REGISTER (10th Mem. Reg. ).
With 10 addressable memories, you have
access to more entries, or intermediate
solutions; less remembering, or writing down,
YOU have to do. And less chance for error.
The stack design also permits X and Y register
exchange, and roll-down to any entry to the
display for review or other operation.
The "lastx” register permits error correction
or multiple operations when a function is
performed, the last input argument of the
calculation is automatically stored in the ‘‘last
. . . . . .
Yes! I'd like to try the Corvus 500 for 7 days
CASH payment: Cheque or money order
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98
ELECTRONICS Australia, December, 1976
x register, which can be quickly recalled to
comect an error, or to perform another
operation using the same number.
3. DIRECT HYPERBOLIC and
HYPERBOLIC RECTANGULAR to POLAR,
and INVERSE. For thpse of you electronic
and computer science engineers who require
access to this specialised application, the
Corvus 500 solves "your” problems.
4. A WORD ABOUT CORVUS 500 12-
DIGIT DISPLAY AND ACCURACY. Finally
you have displayed 12 digit accuracy in k
business format and 10 + 2 in scientific
notation. LED is manufactured by Hewlett
Packard.
FOR THE FIRST TIME you can raise the
number 10 to 199th power or calculate
Factorial (x!) of up to 120. Unbelievable!
5. DIRECT FROM AND TO METRIC
CONVERSION SAVES VALUABLE
KEYSTROKES.
WHAT ABOUT CONSTRUCTION? With so
many features, the next most obvious
question must be in regard to the quality of
the unit itself. We are proud to report the
Corvus 500 to be double injected moulded,
with “tactile” feedback keyboard. The
compact, contoured case is 5 Vi" long by 3"
wide by 1 lA" high and weighs just 8 02.
The COMPLETE CORVUS 500 for $95.00
includes:
• Rechargeable and replaceable Nickel
Cadmium batteries. Optional 3AA batteries.
• Adaptor/Charger.
• Owner’s Handbook.
• Soft canying case.
The Corvus 500 is warranted by the
manufacturer against defects in materials and
workmanship for one year from date of
delivery.
For those of you who have the HP-2-1 or 45 or
any other advanced calculator on order,
aren t you glad you still have the opportunity
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You, our discerning reader will no doubt
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Lighter Side
‘Reviews of other recordings
Devotional Records
HIS HAND IN MINE. Elvis Presley with
the Jordonaires. Stereo, RCA AN LI —
1319.
Unless my memory is playing tricks, I
reviewed this album many years ago, the
jacket adorned with a picture of Elvis,
complete with angelic expression and
lace cuffs! A placid and still youthful pic¬
ture gazes out from this re-release but
the cuffs are gone.
The program is a mix of gently swing¬
ing Gospel songs intermixed with a
sprinkling of up-tempo numbers, with
Elvis swapping the lead periodically with
that excellent backing group, the Jor¬
donaires. The titles:
His Hand In Mine — I'm Gonna Walk
Dem Golden Stairs — In My Father's
House — Milky White Way — Known
Only To Him - I Believe In The Man In
The Sky — Joshua Fit The Battle — He
Knows Just What I Need — Swing Down
Sweet Chariot — Mansion Over The Hill¬
top — If We Never Meet Again — Work¬
ing On The Building.
I imagine that many of Elvis' fans from
way back will have this one in their
collection already but, if not, here it is
again. For those who don't know quite
what to expect, it's typical Gospel plat¬
form entertainment, even conservative
by today's standards, but smooth and
well produced. I noted a trace of inter-
modutation here and there but, overall,
the quality is okay. (W.N.W.)
* * *
FAMILY VOLUMt 5. Stereo, M7,
MLF-136. Cassette FM7C7-136.
If any verification is necessary of the
popularity of the Australian group
"Family", it should follow from the fact
that this is their fifth album. The jacket
picture shows three cheerful young men
in the old tram in Sydney's "Old Spag¬
hetti Factory" restaurant, but who they
are, what instruments they play, and who
else is involved, is left to the listener's
imagination. But it's an excellent program
o^ rock Gospel sound, tailor made for
church youth group listening. The titles
are new to me but here they are:
Welcome/My Kind Of People - He
Ain't Heavy, He's My Brother - Remem¬
ber Whose Child You Are — Front Seat,
Back Seat - Thank You Lord, This House
Runs On Sunshine - Little Country
Church - Oh Boy! Have I Been Stupid!
- I Wouldn't Be Much Of A Friend -
Song For Susan Louise — I Love You.
Diction is not one of the Family's
strong points but their harmony is first
rate, as also is the instrumental backing.
And there's a lot of imagination, too,
behind the planning and arrangement
of the numbers and variations, even to
the simulation of old-time sound quality
for "Oh Boy! Have I Been Stupid".
Elsewhere, it's normal.
Not everyone's choice of Gospel
music but it should go over well with
those who like the mod. sound.
(W.N.W.)
SUPERSTAR BRASS. The Band of
Yorkshire Imperial Metals Top Brass
Series GGS 1508. Astor release.
Records of brass music such as this
must surely dispel any image of the old
style 'band-in-the-park' image with nine
titles ranging from Rossini to Rock as they
say on the sleeve notes.
The titles are Florentiner March - El
Cumbanchero - Holiday for Trombones
— Summertime — The Silken Ladder —
Procession Of The Sardar - The
Typewriter — Largo Al Factotum —
Godspell - Jesus Christ Superstar
Medley.
The quality is excellent, recorded in a
large studio if one can take notice of the
echo on some tracks. Sleeve notes list
nearly thirty musicians and the conductor
is the well known Trevor Walmsley
D.F.C. It is good to hear a group of
musicians like this who obviously enjoy
what they are doing. (N.J.M.)
* * *
101 STRINGS, 20's STYLE Astor Gold Star
Series S-5331 ( M usicassette
BCT5354).
The 101 Strings Orchestra does a
delightful job in re-creating the sound
and style of popular dance music of fifty
years ago, with favourites like: Stardust
RICHARD & PATTI, vocal, with orches¬
tra and chorus. Stereo,. Light
LS-5673-LP. (From Sacred Productions
Aust, 181 Clarence St, Sydney and
other capital.)
I would gather that Richard and Patti
are well known on the American Gospel
scene, such that surnames are redundant.
I'm afraid that, at this remote distance,
"Richard" and "Patti" must suffice.
The first number is an up-tempo item:
"Get All Excited" but the remaining
tracks on side 1 are much more re¬
strained, done with piano, chorus and
gently swinging orchestral backing: Take
A Little Time - For Those Tears I Died
- King Of Kings - Lord Of Lords.
Side 2 is rather similar, opening with
a lively "Greater Is He" followed by
quieter selections: He Giveth More
Grace — Holy, Holy, Holy/ Holy, Holy —
The Lord's Prayer. The final track "The
Church Triumphant" is half-way between
a song and a sermon!
With orchestral accompaniments
arranged and conducted by Larry Dalton,
featuring Larry Dalton on piano, and with
vocal backing by the World Action Sing¬
ers, it's ax very professional performance,
well recorded. Good middle-of-the-road
family Gospel sound, although that final
track may come on a bit strong for Aus¬
tralian ears! (W.N.W.)
— Limehouse Blues — Tea For Two —
Someone To Watch Over Me — Who'll
Buy My Violets — Speakeasy Blues — 3
O'clock In The Morning — Manhattan —
Rhapsody In Blue — Violence.
The style is mainly gentle, ideal for a
background sound for a pleasant social
evening with friends. The exception is the
last track. "Violence", which opens with
a burst of sub-machine gun fire, in stereo
no less. There seems to be a boom in
music from the earlier decades of this
century and music such as on this record
can surely show the reason why.
The quality was a little edgy on the
review copy. (N.J.M.)
* ¥ *
THE BAND OF THE LIFE GUARDS. Sol¬
diers Of The Queen. This Record Co
Ltd L25266. Festival Release.
Some of the best known brass band
favourites, some of them well known as
TV themes, make up the dozen tracks on
this disc. The quality is about the best I
can recall for some time. Many of the
brass band recordings I have heard suffer
in some way, either lacking in highs or
from excessive harshness. The band is
directed by Major Anthony J. Richards,
who, judging by the string of letters after
his name, must be well well up in the
band business.
The titles are: Soldiers Of The Queen
- Rise And Shine - Soldiers In The Park
Reviews in this section are by Neville Williams (W.N.W .). J. Rowe (J.R.). Leo Simpson (L.D.S.)
Norman Marks (N.J.M.) David Edwards (D.W.E.). and Greg Swam (G.S.)
Instrumental, Vocal and Humour
ELECTRONICS Australia, December, 1976
99
LIGHTER SIDE — continued
— The Whitehall Warrior — Sovereign's
Escort — Theme from 'The Regiment' —
The British Grenadiers - Royal Standard
- Lilliburlero - Sarie Marais - Colches¬
ter Castle — There's Something About A
Soldier — The Boys Of The Old Brigade.
The sleeve notes give a brief background
to the tunes. (N.J.M.)
* * *
THE ROARING 20's 16 GREATEST HITS
Enoch Light & The Charleston City
All-Stars ABCS-746 RCA Release.
I don't claim to remember the roaring
twenties but I can certainly remember
these tunes being popular in my
childhood. And Enoch Light and his crew
have done a splendid job of creating the
carefree sounds of dance music of the
era.
As usual with most of Enoch Light's
efforts, the technical aspects of the
recording are beyond any reasonable
reproach.
The titles are: Last Night On The Back
Porch — I Wonder What's Become Of
Sally — Rain — That's My Weakness Now
— Sonny Boy — Rose Of Washington
Square - California Here I Come -
Somebody Loves Me - The Sheik Of
Araby - Singing In The Rain - Sleepy
Time Gal — Margie — Ma He's Making
Eyes At Me — Baby Face — April Showers
- I'm Sitting On Top Of The World.
(N.J.M.)
GOLDEN HOUR PRESENTS WARM
STRINGS GH 612 Astor Release.
If you are seeking a pleasant record as
a background for a quiet social evening
at home this would be a good choice,
with twenty favourites played by an
orchestra with plenty of lush strings to set
the mood. A few of the tracks to illus¬
trate: Memories Of You - Slow Boat To
China - Beautiful Dreamer — Singing In
The Rain - On Dream Street - Night And
Day - All The Things You Are - Yester¬
day — Smoke Gets In Your Eyes — Three
Coins In The Fountain.
The quality varies somewhat, no doubt
due to putting thirty minutes playing time
on each side but, in the context of
background music, this can be forgiven.
(N.J.M.)
+ * *
HARMONICA MAGIC. Lubomir Oleva
with the Ostrava Radio Orchestra,
conducted by Pavel Stanek. Stereo,
Astor GGS-1494.
To the short list of harmonica vir¬
tuosos, headed by Larry Adler, it would
certainly be appropriate to add the name
of Czech born Lubomir Oleva. Although
the jacket notes stress that he is a
physical education instructor by profes¬
sion, with music only as a hobby, you
would never guess as much from listen¬
ing to this recording. His technique is as
sensitive as it is flawless, as befitting one
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100
ELECTRONICS Australia, December, 1976
whose early training was on violin.
Side 1 carries a half dozen tracks, all
modern transcriptions of light classics;
Ciocirlia - Danza Espanola - Clair De
Lune - Hora Staccato - Air On A G
String — Sabre Dance. These give way to
a new and different arrangement of
modern standards on side 2: La Mer -
Mexican Dance - Lonely Night Rider -
Stardust — Isn't It Romantic? — Le Grisbi
— Make Love To Me.
If you have an interest in the har¬
monica, you'll throroughly enjoy this
one. Even if you don't, you could still find
it pleasant, because the harmonica is
merged so skilfully with the Ostrava
Orchestra. Apart a slight touch of
"stringiness" in the strings, here and
there, the overall quality and stereo
spread is good. (W.N.W.)
* * * .
WOODY HERMAN. Vol 2 With Charlie
Byrd and Tito Puente. Astor Gold Star
GGS 1503.
Originally recorded in 1958, this album
has been remastered from 78's. Con¬
sidering this, the quality is fairly good.
Side one carries the lengthy 'Summer
Sequence' followed by Latin Flight-New
Cha Cha and Mambo Herd. Side two
consists of Tito Meets Woody-Cha Cha
Chick— Carioca— Blue Station— Pillar To
Post.
The theme is mainly Latin as can be
seen from the titles and I get the feeling
that there has been no attempt to
"rechannel for Stereo", as switching from
mono to stereo showed no noticeable
difference. I remember most of these
tracks being released on a 'World Record
Club' disc some years ago; it would
present Woody at his peak. (N.J.M.)
★ ★ ★
FAREWELL MY LOVELY. United Artists
L35734. Festival release.
This is another of those sound-track
records that hold little interest unless you
have seen and enjoyed the movie so
much that you want to re-live it by way
of the music.
The film stars Robert Mitchum -and
Charlotte Rampling amongst others, in
what must be another 'Marlowe' detec¬
tive story. The titles are: Marlowe's
Theme — Velma — Mrs Grayles Theme
- Amthor's Place — Mrs Florian Takes the
Full Count — Marlowe's Trip — Convales¬
cent Montage - Take Me To Your Lido
- Three Mile Limited - Moose Finds His
Velma - End Title.
The music tends to be a mixture of
styles and the quality is good. (N.J.M.)
★ ★ ★
BING CROSBY. AT MY TIME OF LIFE.
United Artists L 35889. Festival
release.
With the release of this record, Bing
Crosby celebrates fifty years of show
business, and demonstrates that he has
lost little of the vocal skill that has made
him a household word throughout the
world. The titles range from a gentle:
"How Are Things In Glocca Morra?" to
an uptempo "I Got Rhythm". Other
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hi-fi
WT.GD122T
Why the cannon on your 1812 Overture
sounds more like a popgun.
A rather unfortunate situation
occurs during a recording session.
Because the dynamic range of
most recording equipment doesn’t
equal the dynamic range of live per¬
formances, the loudest sounds end
up being very much compressed,
while the softer sounds have to be
lifted above tape noise.
So no matter how good your
equipment is, it will never ever give
a true performance.
Introducing dbx.
Fortunately for the home hi-fi buff
there ’s now an extremely effective
solution available.
The dbx 117.
Basically it’s a dynamic range
enhancer that works on the signal’s
voltage level without changing the
frequency response. (Unlike other
systems that are designed merely to
filter out high frequencies.)
And attached to any good system it
will noticeably increase the entire
dynamic range of any signal put into
it. While at the same time reducing
surface noise.
So now your softs become even
softer. While your louds, especially
your crescendo’s, become much
more dramatic when they finally
reach the top.
Consequently giving the recorded
performance both more body and
definition.
dbx will also improve the sound
of your older records. So there’s
less need for you to have to replace
them. (The dbx 1 1 7 will also help
reduce hiss from FM broadcasts as
well as your tapes.)
In fact should you desire to test
the dbx before purchase, we then
suggest you contact one of our
dealers listed opposite and politely
ask him to play you a copy of the
1812 Overture.
Should you still have a few
reservations then all we have to
say is that perhaps the 1 8 1 2
Overture was recorded featuring
a popgun.
Or your ears aren’t as good as
you thought they were.
AUR19
Where to hear
the 1812 Overture with
cannon, not corks.
N.S.W.
SYDNEY CITY
Douglas Hi Fi. Kent Hi Fi.
D.ME. Hi Fi. Instrol Hi Fi.
EASTERN SUBURBS:
Woolloomooloo— Convoy Sound.
NORTH SHORE:
Chatswood— Autel Systems.
Crows Nest— Allied Hi Fi.
Gladesville— Hi Fi Hat.
Chatswood— Milversons.
Brookvale— Riverina Hi Fi.
WESTERN SUBURBS:
Fairfield— Bing Lee Electronics.
Summer Hill— Fidela Sound.
Parramatta & Westfield— Grammophone Shop.
Parramatta— Milversons.
Parramatta & Bankstown— Miranda Hi Fi.
Concord— Sonata Music.
SOUTH
St. Peters— Dyna Stereo.
Miranda Fair— Miranda Hi Fi.
LIVERPOOL: Miranda Hi Fi.
WOLLONGONG: Sonata Hi Fi.
GOSFORD : Miranda Hi Fi.
NEWCASTLE : Ron Chapman Hi Fi.
Newcastle Hi Fi.
MAITLAND : Hunter Valley Electronics.
TAREE: Godwins Hi Fi.
LISMORE: Lismore Hi Fi.
A.C.T.:
Pacific Stereo. Duratone Hi Fi
VICTORIA:
MELBOURNE CITY:
Douglas Trading. Nat. Sound.
Allens Music. Southern Sound.
Instrol Hi Fi.
MELBOURNE SUBURBS:
Hawthorn— Tivoli Hi Fi.
Nth. Caulfield— Soundcraftsman.
Moorabbin— Southern Sound
Mordialloc— Mordialloc Hi Fi.
—Denman Audio.
Belmont— Belmont Stereo.
Warnambool— A. G. Smith.
QUEENSLAND:
BRISBANE CITY :
Reg Mills Stereo. Tel Air Electronics.
Stereo Supplies.
BRISBANE SUBURBS:
Redcliffe-Hi Fi Sales (O’ Id.) Pty. Ltd.
Ashgrove— Living Sound Centre.
Tingalpa— Todd Hi Fi.
Ipswich— Ipswich Hi Fi.
SOUTH AUSTRALIA:
ADELAIDE CITY:
Allans Music. Hi Fi Acoustics.
Challenge Hi Fi.
ADELAIDE SUBURBS :
Blackwood— Blackwood Sound.
St. Peters— Sound Dynamics.
TASMANIA:
HOBART:
Quantum. United Electronics.
SUBURBS:
Burnie— Audio Services
WEST. AUSTRALIA
• PERTH:
Alberts Hi Fi.
Leslie Leonards.
Audio Centre.
Japan Hi Fi.
Or write to Auriema (A/asia) Pty. Ltd.
P.O. Box 604, Brookvale, N.S.W. 2J00
Telephone 939 1900 AUR19
LIGHTER SIDE
tracks are: At My Time Of Life - Cabaret
- Something To Remember You By -
Heat Wave — My Heart Stood Still — Raz-
zle Dazzle - Hello Dolly - Looking At
You - I'll Never Fall In Love Again -
Thou Swell - With A Song In My Heart
- Great Day.
With the exception of the title track
which was recorded in Los Angeles, the
album was made in England with the
backing of the Pete Moore Orchestra.
The original lyrics range from 1927 to
1976 so the time span is certainly indica¬
tive of Crosby's influence on the music
scene. (N.j.M.)
★ ★ ★
MUSIC FROM THE GREEK ISLANDS
Volume 2. The Trio Orfeo. RCA Cam¬
den stereo VCL1— 0036.
Here is a talented trio who produce
music that is often almost Latin-American
in flavour, while still maintaining its
Greek overtones. Even those who do not
enjoy most Greek music should sample
this disc. Recording quality is very good.
Recommended.
Track titles are: Imittos — Boy On A
Dolphin - Moustafa - O Sklavos Sou
Ime (I Am Your Slave) - Siko Horepse
Syrtaki (Get Up And Dance The Syrtaki)
- Bepe's Solo - Anihe Apopse Ourania
(The Skies Open Up) - The Pearl Fisher¬
man - Ego Ke To Gaidouraki Mou (Me
And My Donkey) - Stin Kaliva Ti Diki
Mou (In My Small Hut) - Isos Na
Methimate (She May Remember Me) -
Sou Topa Mia Ke Dio, Ke Tris (I Told You
Once, Twice, Thrice). (L.D.S.)
* * ¥
LOOK MY WAY. Rosemary Clooney.
United Artists L35924. Festival
Release.
It is a long time since I've heard a song
from Rosemary Clooney and this album
only points up what we've been missing.
Back ih the fifties, you could always hear
one of her latest hits, like 'Botch- A Me'
and Come On-A My House' on steam
radio and this collection of mainly new
hits is very welcome. Some of the titles
are: Half As Much - When Will I Be
Loved - Storms Never Last - Look My
Way - I'm Not Lisa - Singing The Blues
- When You Got Love - The Very
Thought Of Losing You.
The recording was made in RCA's
Nashville Studios, a virtual guarantee of
high recording quality and the sleeve
notes list all the supporting artists, inclu¬
ding the Jordanaires. (N.).M.)
* * *
THE ARTISTRY OF NELSON EDDY.
Everest, Astor Release GGS 1499.
Anyone with a touch of grey around
the temples will remember the MGM
musicals starring Jeannette McDonald
and Nelson Eddy. This record will bring
back the sound of one of those voices
in vocal settings of favourite classical
excerpts.
Most of the tunes will be remembered
as hits of the early post-war period, titles
like: Tonight We Love, based on
Tchaikovsky's piano concerto in B flat
minor and 'Story Of A Starry Night' from
the same composer's Sixth Symphony.
Others are: The Lamp Is Low — My
Reverie - Till The End Of Time - Strange
Music - Full Moon And Empty Arms -
Love Serendade - Stranger In Paradise
— As The Years Go By - If You Are But
A Dream.
The orchestral backing by Skitch Hen¬
derson suits the romantic mood set by
the songs to make up a most enjoyable
record with excellent quality. (N.J.M.)
★ ★ ★
THE KINKS' GREATEST: CELLULOID
HEROES. The Kinks. RCA Victor
APL1-1743.
While Ray and the other Kinks have
not renewed their contract with RCA Vic¬
tor, it appears that their existing tracks are
still going to be pushed. This record is
mainly filled with material from the 1972
era. In fact, quite a lot of the tracks
appear to have been lifted from the
"Everybody's In Show-biz, Everybody's
A Star" album of that year.
Tracks featured are: Everybody's A Star
(Starmaker) — Sitting In My Hotel — Here
Comes Yet Another Day (live) — Holiday
(live) — Muswell Hillbilly — Celluloid
Heroes - 20th Century Man - Sitting In
The Midday Sun — One Of The Survivors
— Alcohol (live) — Skin And Bone (live)
— A Face In The Crowd.
If you are a devout Kinks fan like me,
then you will appreciate this album, as
some of the tracks are different from the
more widely known versions. And Reg
Livermore fans will recognise the last
track on the first side (Celluloid Heroes),
which is possibly the best Kinks' track of
all time.
As is usual with releases on this label,
the quality of the recording is excellent,
with very little surface noise, and only
slight traces of distortion. (D.W.E.)
* * *
TURNSTILES. Billy Joel. Stereo. CBS
Records SBP 234797.
After his success with "Piano Man", I
was expecting a lot from this album and,
happily, I was not disappointed. From the
opening track to the closing one, this
record is one long enjoyable experience.
Aided by capable session men, and with
his own excellent keyboard work to back
him up, Billy gets into his stride in the first
track, and never looks back from there.
All the lyrics are provided on the inner
sleeve of the album cover, so it is pos¬
sible to gain an insight into the songs
without having to strain the ears. But, in
any case, Billy has excellent diction.
I won't attempt to analyse the album,
but I will give you my thoughts on the
last track. This is entitled "Miami 2017
(Seen The Lights Go Out On Broad-
ELECTRONICS Australia, December, 1976
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LIGHTER SIDE
way)", and it is really superb. It is a
science fiction fantasy, and it evoked
quite fantastic imagery in my mind. If you
sample any tracks at all, sample this
one.
Overall, I can definitely recommend
this album, both technically and aurally!
(D.W.E.)
* * ¥
ELECTRIC WARRIOR. T. REX. Cube
Records Hifly 6. RCA release.
Marc Bolan and T. Rex have been
around the scene for quite a while now,
and they have been quite successful to
date. This record appears to be a reissue
of an earlier (about 1971) album, and as
such is only of interest to collectors and
those who missed out the first time
around.
Tracks featured are: Mambo Sun -
Cosmic Dancer - Jeepster - Monolith -
Lean Woman Blues - Get It On - Planet
Queen — Girl — The Motivator — Life's
A Gas — Rip-Off. Recording quality is
adequate only; there are traces of both
background noise and distortion.
(D.W.E.)
★ ★ ★
SECOND CHILDHOOD. Phoebe Snow.
Stereo. CBS SBP 234799.
This is Phoebe Snow's second album,
and although I have not heard her first
one, judging by this effort it must have
been fairly good. Phoebe has a pleasant,
melodious voice, which she uses to full
advantage. Her exact style is difficult to
categorise, but has some resemblance to
that of Rita Coolidge.
Tracks featured are: Two Fisted Love
— Cash In —Inspired Insanity — No
Regrets - Sweet Disposition - All Over
— Isn't It A Shame — Goin' Down For The
Third Time — Pre-Dawn Imagination —
There's A Boat That's Leavin' Soon For
New York. Technically, the record is
good, with a very clean sound. (D.W.E.)
* * *
CONEY ISLAND BABY. Lou Reed. RCA
Victor APL1-0915.
AEGIS PTY. LTD.
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Lou has gone back to basics for this
album. It is a mixture of hard and soft
rock, with his unique "talk/sing" vocal
style still dominant. The songs on this
album seem to veer away from his more
usual depressing subjects, and at times
become even slightly humorous.
The eight tracks are as follows: Crazy
Feeling - Charley's Girl - She's My Best
Friend — Kicks — A Gift — ooohhh Baby
— Nobody's Business — Coney Island
Baby. The tracks I was impressed with
were "She's My Best Friend" and "Coney
Island Baby". The first track on the
second side is sure to meet with a mixed
reception from the fairer sex.
Record quality is average, with some
background noise, although this is not
obtrusive. (D.W.E.)
102
ELECTRONICS Australia, December, 1976
Popular cassettes:
MOTORING MUSIC 5. The Floyd Harris Orchestra. Dolby
stereo cassette, Contata A-109. (From Goldring Sales & Ser-
vice.)
I seem to have remarked before that the Contata cassettes
impress most with programs that have been specifically
chosen for drive-time listening. The sound is varied from track
to track, in this case by the introduction of Abert Lizzio and
the Solisten, and Otto Weiss with the Seinem Ensemble. So
you get a mix of orchestral, organ, and chorus, with an evident
continental flavour. The tracks:
Dance Of Time - Younger Day - Party Snake - Narcissus
- Hello Smarty - Bianca - Pajaro Serrano - Viens, Viens -
Danny Boy - Red Beans - Tie A Yellow Ribbon -
Guaguqnco.
The overall quality is about average for pre-recorded cas¬
settes but, as I said, the program content would be excellent
for drive time listening or as background in the home. Remem¬
ber that it's Dolbyised, so throw the Dolby switch or turn down
the treble a notch. (W.N.W.)
LOVE IS A MANY SPLENDOURED THING. Ray Conniff, his
Orchestra and Chorus. Stereo, cassette, Harmony (CBS)
HC-1136.
Ray Conniff and his tuneful orchestra and chorus set an
amorous mood with "Love Is A Many Splendoured Thing"
followed immediately by "Lover, Come Back To Me". But, if
the listener was in any danger of embarking on a sentimental
journey, an up-tempo "Blue Moon" could pull them up short.
It's followed by "Love Has No Rules" and "just Kiddin
Around".
Side 2 offers: "Moscow Nights", "Early Evening", "Yellow
Rose" and "Just One Of Those Things"-the whole adding up
to something over 20 minutes of average middle-of-the-road
program. Quality is also average, not really hifi fare but quite
okay for casual or drive-time listening. (W.N.W.)
I'M NOT IN LOVE. Tony Christie. Stereo Musicassette, MCA
(Astor ACT 2664).
A typical popular vocalist, Tony Christie is at great pains to
make the point as per the title track, with twelve numbers:
Queen Of The Mardi Gras - Like Sister And Brother - Love
Hurts - I'm Not In Love - Feelings - Part Time I Love -
Nobody Cried — No Other Love — Wall Of Silence — The
Way We Were - Drive Safely Darlin' - Somewhere In The
Night.
With accompaniments ranging from pensive piano and sen¬
timental strings to rhythm and rock, it's a wide ranging
program that should please those that like the Tony Christie
style. The sound quality is okay. (W.N.W.)
THE BEST FROM BERT KAMPFERT. Played by the Sid Sidney
Orchestra Stereo Dolby cassette, Contata A-118. (From
Goldring Sales & Service.)
Despite the promise of the title, the TDK tape and the Dolby
processing, I found this cassette to be anything but "the best .
The Sid Sidney Orchestra is okay but quality is suspect from
the very beginning where the lower level orchestral ambient
seems to be surging, maybe suggesting that the Dolby circuitry
was acting up. And, elsewhere, string tone is often noticeably
coarse.
A pity, because there are plenty of popular numbers: Stran¬
gers In The Night - 3 O'clock In The Morning - African Beat
— That Happy Feeling — Michaela — The World We Know
- Meeting Again - Spanish Eyes - Swinging Safari - Thank
You - Hold Me - Red Roses For A Blue Lady - Wonderful
By Night - Down By The Riverside.
You want it mainly for drive time listening? Yes, it would
be okay for that but not for the hifi situation. (W.N.W.)
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ELECTRONICS Australia, December, 1976
103
An Introduction to Digital Electronics — 1 1
Encoding & Decoding
Information is usually handled within digital systems in coded form,
as this tends to be more economical of circuitry. At the interface between
humans and systems, it therefore becomes necessary to perform encod¬
ing and decoding. This chapter looks at the basic ways in which these
operations are performed.
by JAMIESON ROWE
As we have seen in earlier chapters,
digital circuits and systems are often used
to convey, process or acquire information.
The information may consist of either
numerical data or messages, or a mixture
of both, but whatever its content it is nor¬
mally capable of being expressed in
human language using alphanumeric
symbols.
While the information is normally in
human language form when it ultimately
emerges from a digital system, and also
before it may be fed into a system, within
such a system it generally exists as an
electrical, magnetic or perhaps even an
optical representation. And typically this
representation consists of suitable com¬
binations of two discrete values of vol¬
tage, current, or magnetic or optical flux.
Although the representation may be a
direct one— for example, using 26 dif¬
ferent digital signals to represent the 26
alphabetic characters, this is rather inef¬
ficient and is not usually done. Instead the
information is usually handled in encoded
form, as we have seen, using each of the
various unique truth-value combinations
of a group of binary digits or "bits" to
represent one of the usual human lan¬
guage symbols.
Encoding gives a considerable increase
in information-carrying efficiency,
because the truth-value combinations
provided by a group of bits rises exponen¬
tially with group size. If there are N bits
in the group, the number of unique truth-
value combinations available for encoding
is equal to the Nth power of 2.
Four bits accordingly provide 1 6 truth-
value combinations, enough to encode
the 1 0 decimal digit symbols with 6 com¬
binations to spare. And as we saw in chap¬
ter 7, seven bits provide no less than 1 28
truth-value combinations, sufficient to
encode all of the alphanumeric and con¬
trol characters of the ASCII code.
When information is to be fed into a
digital circuit or system then, it is
generally first processed by a type of cir¬
cuit known as an encoder. Conversely
when information is to emerge from a
digital circuit or system, it is generally
processed by a complementary type of cir¬
cuit known as a decoder. In the remainder
of this chapter we will look at the way in
which these encoder and decoder circuits
operate.
As the name itself implies, the function
of an encoder circuit is to accept any one
of a number of different input signals, and
generate in response to each one a code
"word" or group of bits having a pre¬
assigned unique combination of truth
values. As we have seen, the number of
bits in the generated code word will
depend upon the number of different
input signals the encoder is required to
handle.
In its most basic form, an encoder con¬
sists of a set of multi-input OR gates, with
one gate for each of the code bits.
A simple 3-bit encoder is shown in Fig.
1 . Here there are seven inputs to the en¬
coder, provided by a set of pushbutton
switches, and the encoder is designed to
provide output code words which are sim¬
ply the binary equivalents of the digits
1-7. This is shown in the truth table.
104 ELECTRONICS Australia, December, 1976
The actual encoding is done by con¬
necting each input line to an input of those
gates required to produce a logic 1 output
for the appropriate output code. Thus the
"1" input line connects only to an input
of the B1 gate, while the "3" input con¬
nects to input of both the B2 and B1
gates. Similarly the "7" input connects
to inputs of all three gates.
Note that when none of the input but¬
tons is pressed, all three gates will be dis¬
abled, and the output lines will all be at
the 0 logic level. This corresponds to the
eighth possible truth-value combination
provided by three bits, and is therefore
shown in the truth table for completeness.
However with this simple circuit it would
not be possible to have a "0" input but¬
ton, because it would not be connected
to the gates and would therefore be
ineffective.
If all of the possible truth-value combi¬
nations of an encoder are to be utilised
for coding, it is necessary to modify the
basic encoder circuit by adding a further
multi-input OR gate, with one input con¬
FIG. 3 : INTEGRATED 4 BIT BINARY
(HEXADECIMAL) ENCODER
nected to all input lines. This then
produces a logic 1 output whenever any
of the keys are pressed, allowing even the
"all zeros" truth-value combination to be
used for coding.
This is shown in Fig. 2, where as .you
can see the 10-input gate at the bottom
INPUT
OUTPUTS
01
02
03
04
KP
(NONE)
0
0
0
0
0
0
0
0
0
0
1
1
1
0
0
0
1
2
0
1
0
0
1
3
1
1
0
0
1
4
0
0
1
0
1
5
1
0
1
0
1
6
0
1
1
0
1
7
1
1
1
0
1
8
0
0
0
1
1
9
1
0
0
1
1
10(A)
0
1
0
1
1
11(B)
1
1
0
1
1
12(C)
0
0
1
1
1
13(D)
1
0
1
1
1
14(E)
0
1
1
1
1
15(F)
1
1
1
1
1
of the diagram is used to generate the
required "key pressed" signal. This can
be used by subsequent circuitry to trigger
processing of the generated code word.
The decoder shown in Fig. 2 generates
four code bits, and is arranged to perform
encoding of 1 0 inputs into the 842 1 BCD
code. You may care to draw up a truth
table based on the circuit connections, to
verify that this is the case.
Although encoder circuits may be
produced by connecting up discrete gates
along the lines of Figs. 1 and 2, integrated
circuit manufacturers have largely made
this unnecessary by producing pre¬
packaged encoder circuits. These may be
treated as functional "black boxes", with
a set of inputs and output whose rela¬
tionships are given by a truth table.
This is illustrated in Fig. 3, which shows
the logic diagram and truth table for an
integrated 4-bit binary encoder which
provides encoding for all 1 6 possible
inputs, in addition to a "key pressed" or
KP output. Such an encoder could be
used to handle numerical information in
either hexadecimal form, as shown, or in
normal decimal form by simply ignoring
inputs 110-11 5.
Simple encoders of this type are
typically* used to accept information from
small input keyboards, and prepare
equivalent code words for use in a com¬
puter, calculator or other digital system.
Where a large number of input keys are
to be encoded, in theory it is possible to
expand the basic OR-gate encoding
scheme to provide the required number
of code bits and input lines. However, in
practice this can become rather clumsy,
involving numerous connections and
gates with large numbers of inputs.
As a result designers of large keyboard
encoders tend to use one of a number of
modified encoding schemes. Mostly such
schemes involve connection of the keys
into a two-dimensional array or "matrix",
and augmenting the basic OR gate system
with some sort of sequential scanning.
This will be discussed in chapter 12.
For the present, there is one further
type of simple encoder circuit which
should be discussed. This is the so:called
priority encoder.
A priority encoder is not generally used
ELECTRONICS Australia, December, 1976
105
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ELECTRONICS Australia, December, 1 976
for decoding information from a key¬
board, -fbut for responding to logic signals
generated by preceding digital circuits.
Like X\\e simple encoder of Figs. 1 , 2 and
3 it produces a unique output code word
for each input, but there is an important
difference. The various inputs are arran¬
ged inrJ'order of priority ", so that if two
or mork»input signals are applied at the
same time, the encoder generates the out¬
put code corresponding to the input with
the highest priority, effectively ignoring
the others.
Why do this? Well, there are quite im¬
portant applications in digital circuitry
where a system— such as a computer or
controller— must respond to a number of
signals, but some of the signals must be
regarded as more 'important'' or more
"urgent" than others.
An example of this is the "interrupt"
facility on many computers. Here the con¬
trol circuitry of the computer is provided
with a means whereby it can be forced to
"drop what it is doing", and handle an
urgent data input or other transaction.
There are often a number of interrupt
sources, and it is generally necessary to
give them an order of priority— so that the
most important transaction cannot be
interrupted by less important ones, and so
on. A priority encoder is generally used
at the interrupt inputs, to both provide an
encoded identification for the interrupt
signal source, and to ensure that the
source with the highest priority takes
precedence.
A three-bit priority encoder is shown in
Fig. 4. As you can see, it has a set of AND
gates ahead of the actual encoding OR
gates, to establish the priority order of the
signal inputs.
If you trace through the logic, you will
find that input 7 takes priority over all of
the other signal inputs. Then if input 7 is
clt logic 0, input 6 takes priority over the
remaining inputs, and so on.
The encoder also has an enable input
and output, to allow a number of similar
circuits to be cascaded if a larger priority
encoder is required. The encoder only
works if the enable input is at logic 1 , and
only produces a logic 1 level at its own
enable output if (a) the enable input is at
logic 1 , and (b) none of its own inputs are
at logic 1 .
The enable input would normally be
driven by the enable output of a "higher
priority" encoder, while the enable output
could be used to drive the enable input
of a "lower priority" encoder. The enable
input would otherwise be connected to
logic 1, if the encoder were being used
alone or was the one in a group with the
highest priority. Similarly the enable out¬
put could be ignored if the encoder were
used alone, or was the one in a group with
the lowest priority. Alternatively it could
be used as an active-low "signal present"
output, equivalent to the "key pressed"
output of Figs 2 and 3.
Having looked briefly at basic encoder
circuits, let us now turn to the circuits
which perform the complementary logic
function: decoding.
Essentially, a decoder circuit is one
which accepts information in encoded
form, and regenerates signals corre¬
sponding to the original information
before it was encoded.
Practical decoders do this by having an
array of AND gates, each of which is
arranged to respond to a particular unique
combination of truth-values on the incom¬
ing code bit lines. Normally there is a gate
provided to respond to every possible
truth-value combination of the code bits,
so that all combinations may be decoded.
A basic 3-bit binary encoder is shown
in Fig. 5. As you can see, it has eight AND
gates, each arranged to respond to one
of the eight truth-value combinations pos¬
sible with 3 bits. Apart from the AND
gates there are three inverters, used to
provide complementary versions of the
incoming code signals to those gates
which need them.
Thus to respond to the code combina¬
tion 101, corresponding to octal 5, the
appropriate AND gate must be fed with
B1 , B3 and the complement of B2. Simi¬
larly to respond to 01 1 , corresponding to
octal 6, the next AND gate must be fed
with B2, B3 and the complement of B1 .
Note that only one output of the de¬
coder can be at logic 1 level at any one
time, because each gate responds to a
unique truth-value combination of the
code bits, and there is a gate for all pos¬
sible combinations.
The simple binary decoding system of
Fig. 5 can easily be expanded, by adding
further gates. Fig. 6 shows a 4-bit binary
decoder, which as you can see is similar
to the 3-bit decoder except that the decod¬
ing gates here have 4 inputs each, and
four inverters are required. This decoder
could be used for decoding hexadecimal
information, or for decoding information
in one of the BCD codes if outputs A-F
were ignored.
It may seem wasteful to suggest that
one would use a decoder like that of Fig.
6 to decode BCD information, by ignoring
6 of the outputs, but the fact is that
nowadays this is very often the cheapest
way of doing the job— thanks to modern
1C technology. Full 4-bit binary encoders
FIG 6 4 BIT BINARY (HEXADECIMAL) DECODER
/
ELECTRONICS Australia, December, 1976 107
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are available as single integrated circuits,
at a price considerably lower than if a 10-
output BCD decoder were built up from
separate gates.
Of course before integrated decoders
became available, designers had to
produce their own decoders using
separate gates, and there was a strong
incentive to be as economical as possible.
This being the case, they found all sorts
of ways of reducing the number of gates
required — particularly where only BCD
decoding was required.
It was soon realised, for example, that
if a decoder was only going to be used
to decode BCD information it didn't really
need to sense every code bit for the decod¬
ing of each and every truth-value com¬
bination. With some combinations, it
became sufficient to sense only some of
the bits, because these were adequate to
distinguish that combination from the
others.
This concept of "sufficient definition"
was used to produce minimal logic BCD
decoders, like that shown in Fig. 7. This
is a decoder for 8421 BCD code, and as
you can see it is somewhat simpler than
if full decoding were used for each of the
10 outputs. Only the "0" and "1" out¬
puts are fully decoded, while the "8" and
"9" outputs have very simple decoding
using 2-input gates. The remaining out¬
puts use 3-input gates, which are still
simpler than the 4-input gates which
would be used for full decoding.
Yet if you trace through the logic, you
will find that this decoder is quite
adequate to decode 8421 BCD code.
Each of the ten truth-value combinations
which are "legal'' in this code will
produce a single and corresponding out¬
put.
Of course the problem with this sort of
decoder is that if a code word becomes
changed somehow into one of the truth-
value combinations which are "illegal" in
the code being used, the decoder will not
handle it correctly. Most likely two out¬
puts will respond at once, which can
cause all sorts of trouble in following
circuitry.
Because of this problem, minimal logic
decoders like that shown in Fig. 7 are not
often used nowadays. There are 10-
output decoders made for BCD encoding,
but these generally use full decoding for
all of the outputs to prevent decoding
errors. In effect they are simply truncated
versions of the full 4-bit binary decoder
of Fig. 6, with only 10 outputs in place
of the full 1 6.
Incidentally although the decoders in
Figs. 5, 6 and 7 are all shown having
"true" outputs, which go to logic 1 when
selected, this is not essential. Many prac¬
tical decoders are made to have "false"
or "active-low" outputs, which go to the
logic 0 level when selected. This is done
simply by using NAND gates for the
decoding, instead of AND gates.
Decoders of both types are made and
used, as each has advantages in certain
applications. It depends largely upon the
108
ELECTRONICS Australia, December, 1 976
decoder at all, but a code translator.
Both 7-segment translator circuits tend
to be grouped in with true decoder circuits
because they are used in similar applica¬
tions.
Finally, it should be noted that in addi¬
tion to providing basic decoding circuits
of the type shown in Figs. 5, 6 and 7,
some manufacturers also provide inte¬
grated circuits which combine a decoding
circuit with a set of flipflop latches, cap¬
able of performing storage.
Such "latch-decoders" may have the
storage latches either before or after the
decoding circuitry, although it is more
common for the latches to be on the input
side as this requires fewer flipflops. But
both types of latch-decoder have their
uses, as many decoding applications also
call for the decoded information to be
stored for some finite time.
INPUT CODE
DECIMAL
SEGMENTS DRIVEW
1
B1
B2
B3
B4
a
b
c
d
e
♦
9
0
0
0
0
0
1
1
1
1
1
1
0
1
0
0
0
1
0
1
1
0
0
0
0
0
1
0
0
2
1
1
0
1
1
0
1
1
1
0
0
3
1
1
1
1
0
0
1
0
0
1
0
4
0
1
1
0
0
1
1
1
0
1
0
5
1
0
1
1
0
1
1
0
1
1
0
6
0
0
1
1
1
1
1
1
1
- r
1
0
7
1
1
1
0
0
0
0
0
0
0
1
8
1
1
1
1
1
1
1
1
0
. 0
1
9
1
1
1
0
0
1
1
FIG. 8 : INTEGRATED 8421 BCD TO 7 SEGMENT DECODER-
WITH DRIVERS AND DISPLAY
circuitry or devices which are to accept the
decoded information — whether it can
most easily cope with the information in
"active high" or "active low" form.
Before we leave the subject of decoders
for the present, there is a further type of
circuit which should perhaps be
described. This is not really a decoder at
all, although the circuits concerned are
usually described as such for con¬
venience. There are only two common
varieties, described respectively as the
"BCD to 7-segment decoder" and the
"hexadecimal to 7-segment decoder".
As the names suggest, these circuits are
used to accept either BCD or hexadecimal
information encoded in 4-bit form, and
produce signals capable of driving one of
the various types of. 7-segment display
device. We will look at display devices in
the next chapter, and it would not be
appropriate to describe 7-segment
displays here in detail. For the moment it
should be sufficient to visualise them as
having seven display segments arranged
in a "squared-8" pattern, so that by
activating the appropriate segments a
variety of symbols may be displayed.
Fig. 8 shows how a "BCD to 7-
segment" decoder is used to drive such
a 7-segment display device from incom¬
ing information in 8421 BCD code. As
you can see from the truth table, the
"decoder"' takes each incoming BCD
code combination and produces signals
on the seven outputs a-g, to produce the
appropriate display. For example when
the input code is 1010, the circuit pro¬
duces a logic 1 at outputs a,c,d,f and g,
to display a 5.
Of course what the circuit of Fig. 8
actually performs is not decoding, but
code translation— it takes information in
4-bit BCD code and translates it into the
special 7-bit code required to drive the
display. The final decoding of the informa¬
tion into human-readable form takes place
in the 7-segment display itself.
Similarly a "hexadecimal to 7-segment
decoder"' takes incoming 4-bit binary
code, and generates the appropriate com¬
binations of output truth values to
produce the 1 6 appropriate hexadecimal
display symbols— in slightly modified
form. Apart from the familiar decimal
symbols 0-9, the additional hexadecimal
symbols are displayed as "A", "b", "C",
"d" and "E"— the two lower-case sym¬
bols being used to avoid confusion with
the numerals 8 and 0.
In short, then, a "hexadecimal to 7-
segment decoder" is again not really a
An example is in frequency counters,
where the BCD output of each decade
counter is normally fed via a latch-decoder
to the display device. The storage pro¬
vided by the latches allows each count to
' be displayed while the next count is taking
place, so that each reading is stable and
readable until it is replaced by the next.
In early counters which used a plain
decoder without latches, each reading
only lasted a short time before the display
"rolled again", as the counter began the
next counting. This made the early instru¬
ments quite difficult to read at times, com¬
pared with modern instruments having
latch-decoders.
ELECTRONICS Australia, December, 1976
109
UN IT REX world-wide marketing and technology
produce two “breakthroughs” in electronic
products! A highly advanced scientific calculator
and a pocket slide rule— both under $15!
UNITREX 95 SL
POCKET
SLIDE RULE WITH FULL MEMORY
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The perfect solution for the
student or technician who needs big
capability in a low-priced calculator!
The Unitrex 95 SL is simple to use, yet has the
ability to solve a wide variety of complex
problems in the office, laboratory or
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• Eight-digit LED red display with
floating decimal point.
• Five-key memory (M + , M— , MR, MC,
MEX) separately stores and
accumulates in separate register.
• Adds, subtracts, divides and multiplies.
• Percentage key with discount and
mark-up capability.
• Automatic constant in all four
basic functions.
• Does chain and mixed calculations
• One-touch square root key.
• Uses algebraic logic. Calculates
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• Credit balance, overflow and
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entry key.
• 9-volt battery for long-term
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MONEY BACK IF NOT DELIGHTED.
❖Refunds will only be payable if the goods
are returned within 21 days of delivery, subject to any overriding State or Federal law.
o
ELECTRONICS Australia December. 1976
CALCULATOR OFHR!
UNITREX 95 SC
ADVANCED SCIENTIFIC
POCKET CALCULATOR
J
i
plus $2.50 for
postage & handling
Th i calculator that solves the one
remaining problem that you had with
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The Unitrex 95 SC is a highly-advanced,
precision electronic calculator that
performs 25 functions— yet costs no more
than calculators with half the capability!
Eight-digit LED red display witlt 5-digit
mantiss. 2-digit exponent and two
signs when the answer is in scientific
notation (from 10" to —10").
Algebraic logic with two levels of
parenthesis.
Advanced memory function that select¬
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register (M + , memory store, memory recall).
Automatically calculates sine, cosine,
tangent, arc sine, arc cosine, arc tangent,
common logarithms, natural logarithms, a
to e power, 10 to a power, reciprocals,
squares, roots and powers.
Special battery-saver circuit fades out
display when keyboard not used for 30 secs.
Clear/clear entry key. Full floating decimal
point, automatic error detection and display.
9-volt battery for
long-term DC operation, 85 cents extra.
HOW TO ORDER: Fill in both sections of the coupon. In each section print your name and full postal address in block letters. Cut the entire coupon out
around the dotted line. Send it with your money order or crossed cheque to this Magazine’s Special Offer (Calculator): P.O. Box 93, Beaconsfield, N.S.W.
2014. Cheque should be endorsed on the back with sender’s name and address and made payable to this Magazine. This offer is open to readers in
Australia only. Please allow four weeks for delivery.
Name .
Address .
State . Postcode.
This Magazine’s Unitrex Calculator Offer 84/76
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Please send me □ Calculator/s 95SL + □ Battery/s
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ELECTRONICS Australia. December. 1976
Books &
Literature
LANTHUR
ELECTRONICS
69 Buchanan Avenue. North Balwyn,
Vic. 3104 P.0 Box 162. Ph. 854061
AUDIOLARM
Type VL-150-RM as used in E.A. audible revers¬
ing alarm. Can give continuous 2900 hz. tone or
beep-beep signal. Voltage and current required
5-16 vdc. @ 17.7-69.4 ma. Diode protected.
$12.50.
Price includes postage.
SANKEN
Hybrid audio modules. 50 watts RMS output into
8 ohms. Supply voltage— 66 @1.1 amp. Max.
harmonic distortion— .5%.
Freq. range— 20hz. to lOOkhz.
Price including postage. $28.50
2 for $55.00
10,20 and 30 watt size also avail.
Price— $7.95, $15.50 & $ 1 9.75 respect.
RESISTORS
10 watt ceramic case. Values from 1 ohm to 1.5k
ohm.
May be assorted— 4 for $2.00
10 for $4.50
Prices include postage.
RESISTORS
20 watt, 20 ohm adjustable.
Few only to clear. 0.60 each
6 for $3.00
Price includes postage.
CERAMIC CAPACITORS
50 volt working.
Values from Ipf. to .1 mfd.
May be assorted— 20 for $2.00
Price includes postage.
POLYESTER FILM CAPACITORS
Values from .001 mfd. to .01 mfd.
20 for $2.00
Values from .01 5 mfd. to . 1 mfd.
20 for $3.00
Above may be assorted.
Prices include postage.
SILICON DIODES
25 amp. 200 piv. stud mount type. Forward or
reverse. Suitable automotive or battery charger
use. $2.00 each
4 for $7.60
Price includes postage.
SEMICONDUCTOR BARGAIN
Pack of 10 each genuine metal cased BC 108
transistors and 1 amp. 400 piv. miniature
diodes.
Price including postage. $3.50
Solid state colour TV
SOLID STATE COLOUR TELEVISION
CIRCUITS by C.R. Wilding. Newnes-
Butterworths, London, 1976. Hard
covers, 195 pages, 234 x 154mm, illus¬
trated by numerous circuit diagrams.
Suggested price in Australia, $12.50.
For those struggling to make the transi¬
tion from valves to solid state and, almost
simultaneously, from monochrome to
colour, this book could be a most valu¬
able reference.
Its most useful role would seem to be
to provide a bridge between the
student's purely theoretical studies, and
the details of practical receiver design.
The first chapter — Devices and
Principles— is worthy of particular men¬
tion. It occupies 28 pages and is almost
a condensed course in solid state in its
own right. The first 16 pages are devoted
to bipolar transistors followed by FETs,
zener diodes, varicap diodes, NTC resis¬
tors, PTC resistors, thyristors, diacs and
triacs. All these devices are described
with a nice balance between basic princi¬
ples and practical uses and circuitry.
The rest of the book is devoted to
specific sections of the colour TV
receiver, as indicated by the chapter
headings: Power supplies, Timebase Cir¬
cuits, Sync Separators, Convergance and
Degaussing, Tuners and IF Amplifiers,
Luminance Circuits, Chrominance Cir¬
cuits, Burst Gates and Reference Oscilla¬
tors, Demodulator and PAL Switch
Circuitry, Signal Amplifying and Output
Stages, Beam Limiters.
While it is not possible to summarise
all these chapters, one, in particular,
impressed me. This is the "Tuners and IF
Amplifiers" section which, among other
things, deals with the latest varicap tuned
and touch control type tuners— types
which have only recently appeared on
the Australian market. Apart from any¬
thing else, it suggests that the book is
right up to date.
In all the. chapters the author strikes a
nice balance between basic principles,
using explanatory circuits, and the prac¬
tical application, using portions of typical
commercial circuits. As with any such
book, it will be most beneficial when
studied in a situation where the reader
has access to sets employing at least
some of the circuits described.
All in all, a book well worth consider¬
ing by anyone making an in-depth study
of current colour TV receiver design
trends.
Our copy from Butterworths Pty Ltd,
586 Pacific Highway, Chatswood, NSW,
2067. (P.G.W.)
Equivalents guide
TRANSISTOR EQUIVALENTS. 9th Edi-
tion. Published in the Netherlands by
De Muiderkring B.V., 1974. Stiff paper
covers, 300 (approx) pages 175 mm x
125 mm, mainly tabulated data. Price
in Australia $5.50.
The problem of reviewing this book
lies largely in the fact that the above
description contains most of the things
that need be said about it. It is, in fact,
a listing of equivalents, with little other
information on the individual types than
silicon/germanium, NPN or PNP. It is
intended to be used in conjunction with
other books giving detailed characteris¬
tics.
My guess is that about 10,000 transis-
This new DECCA Record Cleaner removes dust and grit as your record spins on 1
turntable. It consists of an arm carrying a brush made from a newly-develop
man-made fibre. Its "bristles" are incredibly fine, incredibly soft yet strong, and c
also electrically conductive to remove static as well as dust. The result -Tmprov
sound quality, reduced record wear.
*$13.95 at hi-fi stores and record bars.
Australian agent: British Merchandising Pty. Ltd.,
49-51 York Street, Sydney. Telephone 29 1571.
•Recommended retail price.
GM3E]
Record Cleaner
WORKS AS YOU PLAY...
112
ELECTRONICS Australia, December, 1976
tors are included in the basic list, each
followed by simple classification, as
above, and up to about a half-dozen
approximate equivalents from European,
American and Japanese sources. The last
50 pages, printed on distinctive blue
paper, presumably represent a supple¬
ment containing newly added types.
The book was first published in 1967
but the fact that this is now the ninth edi¬
tion is testimony enough to its usefulness.
Our copy came from Dick Smith Elec¬
tronics (Cat No B2066), 162 Pacific High¬
way, Gore Hill, NSW. Mail orders to P.O.
Box 747, Crows Nest 2065. (W.N.W.)
Video terminals
TV TYPEWRITER COOKBOOK, by Don
Lancaster. Published by Howard W.
Sams, Inc., Indianapolis, 1976. Soft
covers, 214 x 135mm, 256pp, many
illustrations. Recommended retail
price $11.95.
Written primarily for the micropro¬
cessor enthusiast, this latest book by
well-known US technical writer Don Lan¬
caster deals with video terminals and
other peripherals. It is both an introduc¬
tion to their operation and a practical
design guide, and provides quite a lot of
useful information on standards and
established techniques.
Not all of the material would be
directly applicable here, because of the
differing TV standards, etc. Also some of
the sections are rather sketchy to my
mind, and gloss over quite significant
problems. An example is the section on
ASCII-Baudot conversion, which makes
no mention of the complications caused
by the 110/50 baud speed difference.
Nor does the section on cassette tape
interfacing deal with serial data interface
to systems— much harder than a parallel
interface as given.
Still, a very useful reference for those
dabbling in microprocessors.
The review copy came from Prentice-
Hall of Australia. (J.R.)
PC boards
GUIDE TO PRINTED CIRCUITS, by Gor-
don J. King. Published by Fountain
Press, London, 1971. Hard covers, 144
x 223 mm, 140pp, many illustrations.
Recommended retail price $9.00.
Well-known UK technical author Gor¬
don King has aimed this book at the ama¬
teur enthusiast, service technician and
student. It is a basic introduction to PC
boards and their use, with a strong
emphasis on the practical side. There are
chapters on basic PCB technology and
fabrication, together with practical sec¬
tions on home etching and servicing
techniques. The text is clearly written and
well served by illustrations.
In short, a worthwhile reference. The
review copy came from Thomas C.
Lothian Pty Ltd, publishers' agents. (J.R.)
NEW BOOKS
JUST A FEW OF THE THOUSANDS ALWAYS IN STOCK CALL IN OR WRITE. PRICES SUBJECT TO FLUCTU¬
ATION. CORRECT AT TIME OF GOING TO PRESS
1976 ANNUALS
WORLD RADIO & TV HANDBOOK INCLUDING
HOW TO LISTEN TO THE WORLD— Combined
1976 Ed $10.80
A.R.R L. RADIO AMATEURS' HANDBOOK
1976— American Radio Relay League $9.95
TV & TV SERVICING
BASIC TELEVISION PRINCIPLES & SER¬
VICING— B Grob New 1975 edition just
received $14.45
BASIC TELEVISION, Schure, 6 volumes combined
in one. Simiplified text with hundreds of easy to
understand illustrations. The ideal basic training
course. $28.95
COLOUR TV PICTURE FAULTS-Bohlman. Quick
location and repair by means of picture fault
examples in colour $9.30
COLOUR TV THEORY-Hutson $12.00
MONOCHROME JAPANESE TV SERVICE
MANUAL, TAB $5.95
PAL COLOUR TELEVISION FOR SERVICEMEN —
W. C. Cook A new book by an Australian $ 1 5.00
PIN POINT TV TROUBLES IN 10 MINUTES $7.70
SMALL-SCREEN TV SERVICING MANUAL with
circuits including Japanese & U.S. brands,
TAB $8.50
TELEVISION BROADCASTING-Tape and Disk
Recording Systems— Harold E. Ennes $20,.35
TRANSISTOR TV SERVICING MADE EASY-Darr
$6.35
TV SERVICING GUIDE arranged by Trouble
Symptoms— Deane & Young (Our best seller)
_ $4.75
SPECIAL OFFER!
£JAr40~ $12.00
PAL RECEIVER SERVICING. by Seal
Scoop purchase of this outstanding Colour T V. Ser¬
vice book enables us to make this offer.
While Stocks Last!!!
Add Post & Pack
Vic $ 1 .00
Interstate
$1.80
ANTENNA HANDBOOK-A.R.R.L $5.10
AMATEUR RADIO TECHNIQUES-Hawker. RSGB
$7.40
AMATEUR RADIO THEORY COURSE-Ameco
$7.00
BEAM ANTENNA HANDBOOK-Orr $7.00
CUBICAL QUAD ANTENNAS-Orr $5.70
HAM NOTEBOOK-Volume 1 $4.20
HAM HANDBOOK-Volume 2 $5.30
JAPANESE RADIO. RECORDER TAPE PLAYER
SCHEMATIC SERVICING MANUAL $7.25
From Ham Radio Magazine
PIN-POINT TRANSISTOR TROUBLES IN 12
MINUTES $9.65
RADIO & ELECTRONIC LABORATORY
H AN DBOOK — Scroggie New 8th edition
$15.70
RADIO HANDBOOK, New 20th edition $23.45
RADIO VALVE AND SEMICONDUCTOR DATA-
A. M. Ball 10 Ed $5.10
RADIO AMATEURS VHF MANUAL— A. RR.L.
$5.10
SIMPLE LOW COST WIRE ANTENNAS FOR RADIO
AMATEURS-Orr $6.40
TELEPRINTER HANDBOOK, An RSGB Publica¬
tion. $20.80
TEST EQUIPMENT FOR THE RADIO AMATEUR-
Gibson— An RSGB publication $6.65
73 VERTICAL. BEAM & TRIANGLE ANTENNAS—
Noll $6.35
VERTICAL ANTENNA HANDBOOK— Paul Lee. CQ
Series $7.10
VHF-UHF MANUAL. Evans & Jessop. An RSGB
Publication. Revised 3rd Ed enlarged $18.20
HI FI & SOUND
ELECTRIC GUITAR AMPLIFIER HANDBOOK
$8 90
HI FI DESIGNS (WIRELESS W0RLD)-tape. disc.
radio, amplifiers, speakers, headphones $3.00
HI FI LOUDSPEAKERS AND ENCLOSURES-
Revised 2nd Edition— Cohen $8.25
HOW TO BUILD SPEAKER ENCLOSURES-
Badmaieff & Davis $5.70
ELECTRONIC
DIGITAL 1C EQUIVALENTS WITH PIN CON¬
FIGURATIONS De Muiderkring $11.95
DIODES EQUIVALENTS-De Muiderkring
European. American, Japanese types. A com¬
panion to Transistor Equivalents $5.95
DIRECT TRANSISTOR SUBSTITUTION HAND¬
BOOK Direct graded substitutes for nearly
1 2,000 transistors $4.95
ELECTRONICS ENGINEERS REFERENCE BOOK,
Turner. Completely new undated 4th Ed. of this
major reference work, should be in the library of
every serious student and engineer $61.70
GUIDE TO VIDEO TAPE RECORDING, by Editors
of Photographic Magazine $3.30
1C OP-AMP COOKBOOK. Jung, $15.55
INTERNATIONAL TRANSISTOR SELECTOR.
Towers. Over 10,000 U S., Japanese, British &
European Transistors with substitutes TAB
$5.95
IT'S EASY TO USE ELECTRONIC TEST EQUIP¬
MENT, Klein & Gilmore $6.75
110 COSMOS DIGITAL 1C PROJECTS FOR THE
HOME CONSTRUCTOR. Marston. $6.75
PRACTICAL OSCILLOSCOPE HANDBOOK. Vols. 1
& 2 R.P. Turner $10 95
PRACTICAL PA GUIDE BOOK. Crowhurst. How to
Install, Operate & Service PA systems $6.75
SECURITY ELECTRONICS-Cunningham $5.75
SEMICONDUCTOR HANDBOOK-De Muiderkring
Characteristics. Specifications, etc
Part 1 —Transistors $8.95
Part 2— Diodes & Thyristors $7.95
THE WORLD TRANSISTOR CROSS-REFERENCE
GUIDE $10.85
TRANSISTOR ELECTRONIC ORGANS FOR THE
AMATEUR, 3rd edition, Douglas $15.00
TRANSISTOR EQU I V A L E N TS - E uropea n .
American and Japanese. 9000 types and 5600
substitutes. 8th edition $5.95
TTL DIGITAL INTEGRATED CIRCUITS — with
equivalents. De Muiderkring
Part 1 -Sene 740Q-741 32 $8.95
Part 2-Serie 74141-74298 $10.95
UNDERSTANDING AND USING THE OSCILLOS¬
COPE C. Hallmark $6.40
WORKING WITH THE OSCILLOSCOPE. Saunders
$5 95
MANUFACTURERS MANUALS
FAIRCHILD SEMICONDUCTOR — Full Line Con¬
densed Catalog $5.00
FAIRCHILD SEMICONDUCTOR CMOS DATA
BOOK $5.00
GENERAL ELECTRIC SCR MANUAL INCLUDING
TRIACS & OTHER THYRISTORS $5.40
GENERAL ELECTRIC SEMICONDUCTOR DATA
handbook— 1482 pages $8.00
GENERAL ELECTRIC TRANSISTOR MANUAL
$4.00
MOTOROLA SEMICONDUCTOR PRODUCTS
LIBRARY-3 VOLUMES & MASTER INDEX-
DISCRETE PRODUCTS, Series A $20.00
Further volumes sold separately—
VOLUME 4-MECL INTEGRATED CIRCUITS.
Series A $6.70
VOLUME 5-McMOS INTEGRATED CIRCUITS,
Series A $5.85
VOLUME 6— LINEAR INTEGRATED CIRCUITS.
Series A $6.70
National Data Books And Catalogues
CMOS INTEGRATED CIRCUITS $5.70
DIGITAL INTEGRATED CIRCUITS $4. 35
INTERFACE INTEGRATED CIRCUITS $7.60
LINEAR APPLICATIONS. Vol. 1 $7.60
LINEAR INTEGRATED CIRCUITS $7.60
MOS INTEGRATED CIRCUITS $5.70
TRANSISTORS SMALL SIGNAL FIELD EFFECT
POWER $3.25
TTL DATA BOOK $7.60
RCA SOLID-STATE DEVICES MANUAL (Replaces
Transistor Manual) $7.95
RCA SOLID-STATE SERVICING $5.75
RCA LINEAR INTEGRATED CIRCUITS $3.75
Texas Instruments
THE POWER DATA BOOK $6.90
THE TRANSISTOR & DIODE DATA BOOK— Vol. 1
$6 90
THE TRANSISTOR & DIODE DATA BOOK— Vol. 2
$6.90
THE TTL DATA BOOK $6 90
SUPPLEMENT TO THE TTL DATA BOOK $6.90
MAIL ORDERS BY RETURN PLEASE ADD 90c per parcel postage (Vic) $1.70
per parcel interstate
TECHNICAL BOOK & MAGAZINE CO
295-299 Swanston St.. MELBOURNE 3000 Ph. 663 3951
ELECTRONICS Australia, December, 1976
113
New Products
New Nipper 48 colour TV performs well
Nipper 33, Nipper 43 and Nipper 48 are three new solid-state colour
television receivers which will feature in the HMV range for the new
year. We review here the largest of the three, Nipper 48, having a 48
cm (or 20in) diagonal screen measurement.
The picture tube would appear to be a
90-degree type to judge by the overall
depth of the cabinet (462mm) but the
smaller angle does tend to minimise
power consumption (90W total) and to
be less exacting on the deflection cir¬
cuitry.
Although I could find no hint of the fact
in the literature, the receiver is manufac¬
tured overseas to EMI requirements,
conforming completely with local prac¬
tice: isolating mains transformer, X-Ray
protection circuitry, aerial isolating cap¬
acitors and flame retardant cabinet back.
Electrically, the design conforms to
recommendations of the Australian
Broadcasting Control Board, employs full
Pal-D circuitry, and is set for the local
standard white point of 6500 degrees K.
Channel selection for VHF is by
ordinary rotary switch, with a concentric
In introducing the new models, the
EMI Group stresses that they should
build up an even higher reputation for
simplicity of installation and reliability
than even the popular 18-inch HMV
"Braddon" reviewed in these pages in
November last year. Since that time, the
Company's warranty on colour sets has
been extended to 12 months on parts
and labour, and the base cost of sub¬
sequent insurance has tumbled to about
one third — a most attractive proposi¬
tion.
To emphasise the relative freedom
from installation problems, EMI simply
delivered one of the new Nipper 48s into
a typical suburban home situation, no
carton, and carried in by one not-very-
large man. (At 29kg, it can be man¬
handled without too much effort). The
rather puzzled company representative
was told merely to deliver the set and
literature, obtain the necessary signature
and take his leave. The 'householder"
would be the person to connect it up and
switch it on.
Which I did, in due course, standing
it alongside another colour set of known
performance, so that I would have some
basis for comparison. A length of cable
with in-built splitter ensured that the two
would have adequate and identical sig¬
nals on all channels.
At switch-on, EMI had made their first
point! The set immediately produced an
excellent set of pictures from all four
local channels, with no attention to the
AGC or fine tuning, and with not hint of
any problems with purity or conver¬
gence.
Fairly obviously, it was a set that could
be moved around, physically and elec¬
trically, without too much hesitation,
needing only an appropriate aerial con¬
nection to provide first rate pictures. The
set has provision, by the way, for either
300-ohm or 75-ohm aerial connection,
with an in-built 18dB attenuator facility
for strong signal areas. For future UHF
reception a separate 300-ohm UHF aerial
would be required.
One personal impression is worth
mentioning at this point. Having a
26-inch receiver in the home for normal
viewing, my reaction to small colour sets
tends to be one of non-enthusiasm; as
with colour slides and colour movies, the
bigger the screen, the better I like it. But
while the 20-inch screen was obviously
smaller than the 26-inch, I had to con¬
cede that it was no longer "little". Com¬
pared with even an 18-inch, the extra
couple of inches are well worth having.
And there's one other thing that
impresses immediately: the Nipper 48
has a quick heat picture tube, and one
no sooner switches the set on than the
picture comes up to match the sound.
knob for fine tuning. In fact, the fine
tuning will rarely need to be touched,
because the receiver employs full auto¬
matic frequency control, which is norm¬
ally left switched in. The channel selector
is provided with an illuminated indicator
and, when turned to channel 11 (it
actually reads 11 /U), a light appears
behind the UHF tuner dial as well, indi¬
cating potential coverage of UHF chan¬
nels 21 to 69.
The only other obvious controls on the
front panel are for volume, with push-
pull off-on switch, and a locking push¬
button which increases the brightness for
daylight viewing. Closer inspection will,
however, reveal two tiny sockets low
down, near the speaker grille: one for an
earphone (supplied with the set, with 3m
of cord) and the other for a tape recorder
output.
All other controls— colour, brightness,
contrast, and AFC switch— are behind a
door in the front panel, indicating that
once set, they can largely be forgotten.
Other details could be listed if space
were available but they can be obtained
from sales literature covering the
receiver. Of more immediate interest are
the finer points of its performance.
We've already said that it worked well
At right is the new
Nipper 48 colour TV
receiver . A column
stand with castors is
available as a separ¬
ate item . Secondary
controls are access¬
ible behind a door to
the right of the pic¬
ture tube. The re¬
ceiver below is the
baby of the new
range , the Nipper
33.
114 ELECTRONICS Australia, December, 1976
without on-the-spot adjustment; but
how well?
In part, the reduced need for on-the-
spot adjustment is due to the use of a
vertical slot type picture tube in place of
the older dot-pattern, delta gun type. The
advantage can be bought rather dearly,
however, if the vertical slots (or stripes)
are too coarse, since they can reduce
effective definition and be seen as a ver¬
tical line pattern— at least by those with
keen vision. In fact, the slots in the Nip¬
per 48 picture tube are quite narrow and
give no cause for such criticism. Defini¬
tion of detail was right up to standard.
We felt that the highlights were initially
a trifle too bright, even with the bright¬
ness turned down, but this was corrected
by a nudge of the sub-brightness control
—a screwdriver adjustment accessible
through the front panel and the sort of
thing the installer would probably have
reset, had he been given the chance at
the time of delivery.
We also felt that the contrast could
have come down a little further than the
control permitted and this was verified
when we were able to catch a test pat¬
tern. The last step in the grey scale was
being crushed somewhat, but this was
something we elected not to fiddle
with.
With the test pattern available, we
were able to note that the basic vertical
and horizontal grid was indeed rect¬
angular, substantially free from pin¬
cushion effect, and completely free from
any interference between the video sig¬
nal and line sync. The centre circle was
free from any hint of irregularity but it did
measure 30 cm wide by 29 cm high,
indicating the need for a slight reduction
in width.
For all practical purposes, the colours
in the test pattern were identical with
those on the known reference receiver
and, after ail the hoo-haa about white
point settings a few months ago, we were
happy to record that there was no dis¬
cernible difference between the two. In
fact, apart from the slight crushing in the
shadows mentioned earlier, the pictures
were virtually identical in colour values
and definition.
To sum up, our impression of the Nip¬
per 48 is that it is an excellent receiver
and very well suited to domestic situa¬
tions were a small set would be
inadequate, but where a 26-inch model
would be too cumbersome and too
costly. Performance, as delivered, was
excellent, and faulted in minor detail only
because we were able to make side-by-
side comparison with another known
receiver.
If noticed at all under other circum¬
stances, such detail could readily have
been attended to during normal installa¬
tion or follow-up.
Recommended retail price for the Nip¬
per 48 is $663. Further information can be
obtained from EMI dealers around Aus¬
tralia or by mail from EMI Aust Ltd, P.O.
Box 32, Homebush 2140. (W.N.W.)
INFRA-RED INTRUDER ALARM
Housed in an attractive, tamper protected housing, the Raytek BiSpy
model 8500 passive infrared intrusion detector can monitor a sector
of free space measuring 80 degrees by 25 feet. Up to six slave units
can be controlled by the master unit.
Infrared intruder detectors operate by
sensing the change in level of infrared
energy caused by the entry of an intruder
into the protected area. As shown in the
diagram, the BiSpy optical system divides
the protected area into five zones, each
of which is monitored simultaneously by
two independent detectors.
Two independent infrared detectors
(using the same optical system) are built
into each sensing head. Output signals of
the two detectors are processed through
separate amplifiers and trip circuits
before being compared by a summing
gate. Unless both channels simul¬
taneously detect an intruder, the system
will not alarm.
This means that false alarms cannot
occur due to electrical interference or
intermittent component failure in either
channel. By having the sensing area
divided up into zones, it is also possible
to aim the unit so that heat producing
objects such as hot air vents fall between
the zones, and thus do not cause
erroneous alarms.
In order to facilitate such aiming, the
unit is provided with a "walk test"
provision. After mounting the unit in
The BiSpy system uses two detector
channels , also wide-angled detection
zones.
position, a slider switch on the front of
the unit is moved to the appropriate
position. The installer can then walk
about the covered area, and check that
the alarm is triggered in the appropriate
places. This is indicated visually by a
small LED on the front of the unit.
The unit operates from a 12V power
source, which can be either AC or DC.
Current consumption is 50mA. A 12V
0.5AH nickel-cadmium standby battery
can be fitted inside the case. This gives
a standby time of eight hours.
The alarm relay has single pole double
throw contacts, which are rated at 0.06
amps at 130VDC. The tamper switch has
similarly rated contacts.
Measuring 190 x 140 x 90mm, and
weighing only 1 .1 kg, the unit is mounted
in an attractive intercom styled plastic
The Raytek BiSpy model 8500, which
uses a passive infra-red detection sys¬
tem.
case. Slave units are identical in size, but
of slightly lesser weight.
The unit is intended to be mounted
against a wall, with screws through the
back plate. Access to these screws is
obtained by removing the front cover,
which then activates the tamper switch.
This can be either wired in association
with the alarm circuit, or independently
of it.
Up to six type 8520 slave units can be
used with the 8500 master unit. These
slaves receive their power from the mas¬
ter unit, and when an intruder enters their
field of view, they trip the alarm relay in
the master unit. With six slaves in opera¬
tion, the standby time is reduced to a
minimum of four hours.
Other models of both master and slave
units are available with long range
coverage. The slave units are connected
in parallel with 4-conductor shielded sig¬
nal wire. If the tamper switches are
utilized, 6-conductor wire is required.
Units are also available for concealed
and in-wall mounting. The 8500 master
unit in both wide range and long range
versions sells for $264.37 plus tax. The
price for larger quantities is $218.10 each
plus tax. Slave units in one off quantities
cost $176.96 plus tax, while for larger
orders the unit cost reduces to $145.99
plus tax.
Standby batteries are obtainable for
$29.55 plus tax, while slaving cable sells
for 35c per foot, plus tax. Inquiries should
be directed to the Australian agents, Cur¬
rency Handling Systems (Australia) Pty
Ltd, 28-30 Langley Street, Darlinghurst,
NSW 2010. (D.W.E.)
ELECTRONICS Australia, December, 1976
115
NEW PRODUCTS
PUT YOUR
HANDS TO WORK
MAKING MONEY
AS A COLOUR
TV TECHNICIAN
Do you like to find out why things work, or
not work? And do you find electronics an
interesting field? Because there is a demand
for trained and skilled people to service the
millions of pieces of electronic equipment
used every day in Australia. Think how
many colour TV sets have already been sold
in Australia. These will need servicing. And
there are millions of older Black and White
sets that will also require the services of a
good, trained Technician.
If you are interested in electronics, then you
should find out more about the ICS training
for Electronic and Colour TV Technicians.
Send the coupon now, and ICS will return
you a complete Career Program guide that
tells you how the ICS method works and
what the training program teaches you.
You study at home, at your own pace.
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putting your new knowledge to work. And
the study program only asks for about an
hour a day.
Would you spend an hour a day to earn
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Mail the coupon — today!
International Correspondence Schools,
400 Pacific Highway, Crows Nest
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Wide band preamp for instruments
The WB250 Wide Band Amplifier is a
rather unusual piece of equipment
offered by Bright Star Crystals. The main
use for this unit is to increase the effective
sensitivity of frequency counters. Also,
because no actual connection is made to
the equipment to be tested, oscillators
may be measured without interfering
materially with the actual frequency. This
can be a decided advantage, as when
actual connection has to be made to an
oscillator, the frequency may be shifted
to a marked extent, thus giving a false
reading.
The device is a battery operated tran¬
sistorised wideband amplifier, housed in
a handy size metal box. The input sensi¬
tivity is quoted as 500uV, with an output
of lOOmV. The bandwidth is quoted as
from 100kHz to above 500MHz. How¬
ever, a check which I made at the low
frequency end showed that the response
started to fall off significantly at about
300kHz. I understand that by increasing
the size of coupling capacitors in the unit
the low frequency response can be
somewhat improved.
Another check made on an oscillator
operating between 3.5MHz and 4.0MHz
indicated that the device does what is
claimed for it. By placing the probe near
FOR COMMUNICATIONS
NOMIS ELECTRONICS PTY. LTD.
226300
689 SOUTH ROAD.
BLACK FOREST, S.A. (08) 293 4896
And these Suppliers
N.S.W. Martin de Launay. Sydney— 29 5834
Newcastle-2 4741. Wagga-21 4644 Wollongong-28 6020
QLD. Martin de Launay. Brisbane— 52 8467 S.A Neil Muller
Adelaide- 74 1162 Mt. Gambier, SES8 Services-25 5970
W.A. Atkins Carlyle. Perth— 22 01 91 . N.T. Veneman & Wyatt.
Darwin— 81 3491 VIC. JES Electronic Components
Melbourne— 88 5282.
the oscillator and connecting the output
to a counter or a CRO, a good indication
was obtained in each case.
I found the unit easy and convenient
to operate, with the case fitting comfort¬
ably in the hand, with the push-button
switch in the right place. In short, then,
this device should be of considerable
value to anyone involved with low level
oscillators and similar circuits and the
need to make measurements on them.
An additional feature is available as an
option. An inbuilt marker can be
supplied for 455kHz, 10.7MHz, or
29.798MHz. I imagine that other frequen¬
cies could be supplied on special order.
Further details from Bright Star Crystals
Pty Ltd, 35 Eileen Road, Clayton, Victoria
3169. (I.L.P.)
FRG-7
SYNTHESIZED
RECEIVER
for
Amateurs,
Novices,
and
Short-Wave
Listeners.
TECHNICAL DATA
• Electronic Band Changing.
•0.5 — 29.9 MHz. Continuous Coverage.
^Uses Wadley Loop (drift cancellation circuit) to
derive synthesized hetrodyne oscillator signal
• LSB, USB, AM and CW.
• Frequency Readout better than 10 KHz(readable
to 5 KHz).
•Stability within 500 Hz during any 30 minute
period after warmup.
•Better than 0.7 //V for 10 dB S + N/NSSBand
Better than 2 /yV for 10 dB S + N/N AM.
•Selectivity ± 3 KHz at — 6dB, ± 7 KHz at -50 dB.
• Input impedance, high 0.5 — 1.6 MHz.
50-75 Ohm 1.6 — 29.9 MHz.
• 234V AC 50-60HZ or 12V DC (external or internal
8 dry cell).
• Size 340 mm x 153 mm x 285 mm.
FRG-7
$279
Above prices include 8.T Prices and specifications
subject to change.
60 Shannon St.. Box Hill North
ELECTRONIC Vic. 3129
SERVICES Ph 89 221 3
116
ELECTRONICS Australia, December, 1976
Video Technics TV Tuner
Designed specifically to mate with colour and B&W video recorders,
the Video Technics Colour TV Tuner has facilities for VHF and UHF
reception. It is especially useful when more than one program has to
be monitored and recorded at the same time.
The Video Technics Tuner is accom¬
modated in a wide shallow case with up-
to-the-minute styling. It has a black
perspex dial with windows for tuning
meters and the case is timber with a
simulated woodgrain finish. Dimensions
are 482 x 90 x 305mm (W x H x D).
Coverage is provided for all Australian
VHF television stations plus UHF chan¬
nels 25 to 68. Antenna inputs are 75 ohm
coax socket for VHF and 300 ohm
twinlead socket for UHF. Outputs are a
J-standard 8-pin socket for connection to
video recorder, BNC connector for video
line output and 6.5mm jack socket for
audio line. Video output is 1 volt peak-to-
peak and audio output is 700 millivolts
RMS with low output impedance.
Basically, the instrument consists of
separate VHF and UHF tuner modules
together with the necessary power
supplies, and IF and detector circuitry to
provide the video and audio outputs. The
IF and detector circuitry is housed in a
tinplate enclosure and the power supply
circuitry is on a separate PC board. A
standard 3-core mains flex and 3-pin
mains plug is fitted.
The Video Technics tuner is designed
and manufactured in Australia by Video
Hifi Centre who can demonstrate the unit
and provide information on performance
and price. Their address is 2nd Floor, Tel¬
ford Trust Building, 79-85 Oxford Street,
Bondi Junction, NSW 2022.
Puncture Tester
Pictured below is a new high voltage puncture tester made by Tech Instruments
Company Ltd , of japan. It is basically an adjustable high voltage AC power supply
with presettable cut-off current (from 0.5 to 10 milliamps). A component to be tested
is connected across the terminals and voltage applied. If the preset current is
exceeded , a buzzer sounds and an indicator lights. At the same time , the supply
voltage is automatically disconnected from the terminals. A reset button returns the
tester to normal operation for the next component to be tested.
Further information on price and availability can be obtained from the distributors ,
University Graham Instruments Pty Ltd , 706 Belmore Road , Riverwood, NSW.
Standardize on
Cjimbiom
The Guaranteed Electronic Components
•Reg TM Gardner Denver Co
Wire-wrap*
pins and
terminals in
variety and
quantity.
Cambion knows what it takes to make all the
connections in today's sophisticated circuits.
That's why you’ll find a wide range of
CAMBION Wire-Wrap pins with terminals or
jacks readily available. CAMBION pins assure
mechanically strong, reliable, uniform,
durable metal-to-metal and solder-to-metal
connections. Write for our Integrated
Packaging Catalog 1 19A.
ELECTRONIC DEVELOPMENT
SALES PTY. LTD.
27 BUCKLEY ST., MARRICKVILLE.
N S W. 2204
EDS 51 7007
ELECTRONICS Australia, December, 1976
117
NEW PRODUCTS
-that's where the money is!
Stott’s course is totally comprehensive — and includes both sophisticated
electronic equipment and project materials you need to gain a thorough
understanding of servicing techniques.
Divided into three self-contained sections, the course covers:
Part 1 — Introduction to Electronics (theory and practice)
Part 2 — Monochrome Television Receivers
Part 3 — Colour Television, including processing circuitry, service
techniques, fault tracing and trouble shooting techniques.
Like all Stott’s courses, you work with your own instructor who is an expert in
this exciting and rewarding field, at your own pace, in your own home.
If you are a beginner, Stott’s will teach you everything you need to know
concerning television principles and receiver circuitry.
If you are already working in the field, or have completed some studies in
electronics, you may be eligible to enter the course at an advanced stage.
Whether your aim is to enter the TV service industry or whether you wish to
gain a thorough understanding of television theory and servicing as an aid to
sales experience, this is the course which will help you make it!
Other electronics courses offered by Stott’s include:
Radio for Amateurs — Amateur Operator’s Certificate
For full information mail this coupon today:
Stotts^
TECHNICAL CORRESPONDENCE COLLEGE
The name to trust in correspondence education
Please send me, without obligation, full details of the following courses:
Stott’s undertake that no sales counsellor will call.
1 Mr., Mrs., Miss
Age
J Address J
i Postcode
' 159 Flinders Lane, Melbourne.
383 George Street, Sydney,
i stcs 15 290 Adelaide Street, Brisbane.
66 Kina William St. Kent Town, S.A.
89 St. George’s Terrace, Perth.
P.0. Box 3396, Singapore 1.
EA.12.76 I
Audiolarms from C&K
A new series of small, low cost solid
state alarms has been introduced to the
Australian market by C & K Electronics.
The Bell "Audiolarm" range of devices is
claimed to operate in hostile environ¬
ments, unaffected by extremes of
humidity, vibration, altitude or salt
spray.
All models produce a shrill, penetrat¬
ing sound, and operate on a wide range
of supply voltages. No RF noise is pro¬
duced during operation, as no mechani¬
cal parts are involved in sound
generation.
Sound levels of up to 95dB can be pro¬
duced by most models. Some models
operate continuously, while other can be
made to pulse on and off. Models are
also available which can be controlled by
logic signals.
Further information can be obtained
from the Australian distributors, C&K
Electronics Pty Ltd, PO Box 101, Merry-
lands, NSW 2160.
CB dealers wanted
Dick Smith Electronics Pty Ltd is con¬
fident that the PTT Department will soon
approve CB radio in Australia. So con¬
fident that it is seeking reseller/dealers
throughout the country for the Midland
range of CB equipment, for which it is
the Australian agent. Midland Electronics
is claimed to be CB industry market
leader in the US.
Equipment designed for the CB band
may only be operated legally in Australia
at present by radio amateurs and those
who have been granted a permit by the
PTT department. However there are no
restrictions on the sale of equipment.
DSE believe they are one of the few
firms in Australia at present who have the
knowhow, spares and servicing facilities
to make selling CB radio a profitable ven¬
ture. They invited anyone interested in
becoming a Dick Smith/Midland Dealer
to write to Gary Johnson, D.S. Distribu¬
tors, PO Box 747, Crows Nest NSW
2065.
118
ELECTRONICS Australia, December, 1976
Video game
The Video Sport game provides for
Tour games: tennis, squash, handball and
football/hockey. It provides sound ef¬
fects for hit, wall bounce and score, and
also has automatic on-screen scoring.
Playing speed and bat size are both vari¬
able, and playing area is visually defined
on-screen.
The unit operates from six standard D
type cells, and complies with specifica¬
tions published by the PTT Department
in terms of RF radiation.
Priced at $79.50, the Video Sport is
available from Farad Sales Pty Ltd, of 212
Balaclava Road, Caulfield, Victoria 3161.
Mail order sales accepted.
Edge connectors
Locally manufactured PC edge con¬
nector sockets of any required length up
to 85 connectors per side are available
from Amphenol Tyree. The series 225A
connectors can be single or double
sided, with either 0.1 in or 0.1 56in spacing
between contacts. The contacts are
made from a new high tensile material
3 FERGUSON £
Manufacturers of:
Electrical / electronic
equipment, wound
components and
lighting control
equipment.
BRANCHES
IN
ALL STATES
Ferguson Transformers
Pty Ltd.
Head Office
331 High Street. Chatswood
NSW 2067
PO Box 301 Chatswood.
NSW, Australia 2067
Phone: 02-407-0261 _
and are available with gold plating of 0.5,
0.76 or 1.2 microns as desired, with
various tail options.
Further information from Amphenol
Tyree Pty Ltd, 176 Botany Street, Water¬
loo, NSW 2017. Telephone (02) 69 5364.
Paper tape punch
The MACE patented tape punch
shown below is a low cost, low power
unit designed for unattended remote
data recording. It is available from
Measuring and Control Equipment Co.
Pty. Ltd., 9 Mobb^ Lane, Carlingford,
NSW 2118. Telephone (02) 858 3878.
CRASH!!!
Grab yourself a bargain month at Micronics.
Just look at these prices. Irresistible!!!! 555
Timer (mDIP)— for $2. The most versatile I.C.
everybody needs a few at some time or other:
— BC547, BC548, BC549 — 10 for $1.50,
BC557, BC558, BC559— 10 for $1.50, BF198
-5 for $2. BF 185—3 for $2. BC635-4 for $2.
EM404— 10 for $1, EM410— 10 for $1.10,
OA90-10 for 80c, 2N6107-4 for $2, 40250
(2N3054)— 3 for $2.50, 2SA353(AF1 26)— 5 for
$2. Special 2N3055-1 Silicon Power
Transistors — 1 0 for $ 5. Cl 06D S.C.R. (400v,4A)
— 3 for $3.50. Linear I.C.s. — 741 (mDIP)— 40c
ea , LM301, LM307(mDIP)-70c. LM709(DIP)
— 75c, CA3012, CA3013. CA301 8(Can)— 80c
ea Special audio I.C. HAI322, 5.5 Watts Peak
Power incl. Cct diagram — $ 1 . 75 ea. or 4 for $6.
New, super bargains packs. Super saving on
these. Every hobbyist or serviceman needs
these super value packs: — Styroseal pack caps
—New, Top Quality— 20 for $1 Power resistor
pack (Up to 7W Power Resistors)— 20 for $2.50.
Potentiometer pack incl. Dual gang. Single gang
and trimpots (No Junk) — 10 for $2.75.
Semiconductor pack: Fantastic Pack of silicon
germanium transistors and other semiconductors
—20 for $2 Rotary switch pack. Fantastic value
in Rotary switches; you will be amazed! — 3 for
$3.50 For free offer and more specials read
other advertisements in this issue. Page Nos in
Advertisers Index. Post and Pack 60c or extra for
larger parcels.
MICRONICS
P.0. Box 175, Randwick. 2031
CO. PTY. LIMITED
INCORPORATING
P. A. HENDERSON & CO
TRANSFORMER
MANUFACTURERS
• SINGLE & 3 PHASE
TRANSFORMERS TO 20 KVA.
• MOTOR STARTING
AUTOTRANSFORMERS TO
600 HP.
• NEUTRAL REACTORS
8 East St.,
Granville, N.S.W. 2142.
P.O. Box 31 , Phone
637-7870.
“COWPIR”
Cabinets and chassis for all
projects featured in this
magazine are available
from
COWPER SHEETMETAL
& ENGINEERING
□ CASES □ PANELS
□ CHASSIS □ BOXES
□ GENERAL SHEET METAL
WORK FOR THE
ELECTRONICS INDUSTRY
□ WELDING
□ PRESS CAPACITYTO 75
TONS
1 1 Cowper Street,
Granville, N.S.W. 2142
Phone 637-8736
ELECTRONICS Australia. December. 1976
119
FANTASTIC BUSINESS
LOCATIONS TO LET
Ideal for Electronic Service
Business
BANKSTOWN (Sydney)
Hume Highway. 1st Floor
Premises above Dick Smith
Electronics — tremendous
passing traffic, good parking.
RICHMOND (Melbourne)
1st Floor also above Dick Smith
Electronics, large area (over 3,000
sqf.), fully carpeted. Ample
parking in vicinity. Both these
premises are ideal for virtually
any business associated with
sales, manufacturing or service.
A guaranted flow of electronic
enthusiasts would pass the door
each day*.
Apply to "The Manager"
Dick Smith Electronics
656 Bridge Road,
Richmond., Victoria. Ph 42 1614
Dick Smith Electronics
361 Hume Highway,
(Near Chapel Road),
L Bankstown., N.S.W.Ph 709 6600 j
KNOW
Where you are going?
Choose a career in the field
of Electronics - the Nation's
most progressive and fastest
expanding industry
BROADCASTING
COMMUNICATIONS - marine
APPLIED SERVICING
Classes are conducted at
67 Lords Road ,
Leichhardt
Day 9.00 a.m. to 4.00 p.m.
Evenings 6.00 p.m. to 8.30 p.m.
or by Home Study Courses
(except practical instruction on
equipment)
SEND FOR PROSPECTUS
There is no obligation.
NAME. .
ADDRESS
MARCONI SCHOOL OF WIRELESS
Box 218, P.O. Leichhardt 2040.
A service of
Amalgamated Wireless (Australasia) Ltd.
FREE OFFER!!!
Free offer of 5 of BC548 (New Branded) Transistors for
every order over $ 1 0; This month only! Take advantage
of this free offer now! Don't delay! Special purchase
of fresh stock electrolytics and switches. We can sell
these at a fraction of List Prices. Just Look!! Electrolytic
super bargain — 2. 2uf/50v (Single Ended). Top
Quality— 20 for $ 1 . (S.E.) is single ended type, (P) is pigtail
type. The following are single ended types 1uf/25v— 10
for 60c, 2.2uf/25v— 10 for 65c, 10uf/25v— 10 for 70c,
2 2uf / 2 5v— 1 0 for 80c, 33uf/16v-10 for $1,
47uf / 1 6v— 10 for $1.20, 47uf/63v— 10 for $1.60,
10puf/25v-10 for $1.60, 220uf/25v-10 for $1.90.
470uf/25v-10for $2.50, lOOOuf /25v— 10 for $3.50.
100uf/63v— 10 for $2.40, 100uf/l0v-10 for $1.
640uf/16v— 10 for $3. The following are pigtail type:
1uf/350v— 10 for $1.75, 2.2uf/350v-10 for $2.25,
1 Ouf / 3 50v— 1 0 for $3. 22uf/350v-8 for $3.
47uf/350v— 6 for $3. Just arrived new switches. Fan¬
tastic sales of switches. These are top quality switches.
Many miniature types at incredible prices. We brought a
certain quantity so remember, once they are sold out at
these prices, you’ve missed out.ST103A Toggle switch
SPST— 40c ea. or 10 for $3.50, MSPB206R Push button
DPDT— 60c ea. or 10 for $5.50. MSP106D Push button
SPDT— 50c ea. or 10 for $4.50. MST206N Miniature
Toggle DPDT-85c ea. or 10 for $8.MSL203N-5 Rocker
switch DPDT— 65c ea or 10 for $6, MSH203N Rocker
Toggle switch DPDT— 65c ea. or 10 for $6, MSP103C
Push button S.P.-30c ea. or 10 for $2.50, MST406N
Miniature Toggle— $ 1 ea. or 10 for $9, MR3-3 Miniature
Rotary switch — $1.50 ea. or 10 for $13 New panel
meters at Bargain Prices with Blank scale, ideal for mak¬
ing up your own scale, sensitive movement; rugged
construction:— Model SD830, Range DC50 mv, Size
3V4"x4V4"— Only $3.95 ea. Model SD640. Range DC50
mv. Size 2,/2"x3,/4"-Only $3.75 ea Model SD460,
Range DC 1 MA, Size 1 %“x2%"— Only $3.75 ea. These
bargains are not to be missed. Every hobbyist needs a
panel meter at some time or other. Post your order today!!
Money back if not satisfied! Post and Pack 60c or extra
for larger parcels. Your money refunded if not satisfied.
MICRONICS
P.O. Box 175, Randwick. 2031
NOTICE TO ADVERTISERS
Certain provisions of the Trade Practices Act 1 974, relating to consumer protection place
a heavy burden upon advertisers, advertising agents and publishers of advertisements.
Section 52 of the Act imposes a general duty
on everyone (individual and corporation alike)
not to engage, in trade or commerce, in con¬
duct that is "misleading or deceptive. "
In addition Section 53 (read with Sections 6
(3) (c) and 79) makes it a criminal offence
(punishable in the case of an individual by a
fine of $ 1 0,000 or 6 months' imprisonment
and in the case of a corporation by a fine of
$50,000) for an individual or corporation to
do any of the following in trade or commerce
in connection with the supply or possible sup¬
ply of goods or services or in connection with
the promotion by any means (for example
advertising) of the supply or use of goods or
services, namely: -
"(a) falsely represent that goods or services
are of a particular standard, quality or
grade, or. that goods are of a particular
style or model;
(b) falsely represent that goods are new;
(c) represent that goods or services have
sponsorship, approval, performance
characteristics, accessories, uses or
benefits they do not have;
(d) represent that the individual or corpora¬
tion has a sponsorship, approval or
affiliation [he, she or] it does not have;
(e) make false or misleading statements
concerning the existence of, or amounts
of, price reductions;
(f) make false or misleading statements
concerning the need for any goods, ser¬
vices, replacements or repairs; or
(g) make false or misleading statements
concerning the existence or effect of any
warranty or guarantee. "
Apart from the criminal sanction for a breach
of Section 53, an individual or corporation
infringing Section 52 or 53 is liable to proceed¬
ings for injunction and for damages suffered
by an injured party. In vi«w of the obvious
impossibility of our insuring that adver¬
tisement submitted for publication comply
with the Act, advertisers, and advertising
agents will appreciate the absolute need them¬
selves to ensure that the provisions of the Act,
including the sections specified above, are
complied with strictly.
It is suggested that in cases of doubt adver¬
tisers and advertising agents seek legal
advice.
SUNGRAVURE PTY. LTD.
ULTRA-CARDIOID
Unsurpassed 25db
front-to-back
rejection for
critical use.
N0MIS ELECTRONICS PTY. LTD.
689 SOUTH ROAD,
BLACK FOREST, S.A. (08) 293 4896
And these Suppliers
N . S . W . Martin de Launay. Sydney— 29 5834'
Newcastle-2 4741 . Wagga-2 1 4644 Wollongong-28 6020!
OLD. Martin de Launay. Brisbane— 52 8467 S.A. Neil Muller.
Adelaide- 74 1 162 Mt. Gambier. SES8 Services- 2 5 5970
W.A. Atkins Carlyle. Perth-22 0191 N.T. Veneman & Wyatt.
Darwin— 81 3491. VIC. JES Electronic Components.
I Melbourne-88 5282.
120
ELECTRONICS Australia, December, 1976
NEW PRODUCTS
TWO NEW CALCULATORS FROM UNITREX
Two new calculators, recently announced by ^ h'^tweSn faofl itTeS
would haveVbeen found only in much more costly calculators.
The simpler of the two, the Unitrex
95SL, is described by the manufacturer as
a ''Slide-Rule" Calculator and is intended
for students, handymen, technicians or
engineers, who might hitherto have
relied on slide rules, tables-or long-hand
calculations!
It is basically a 4-function calculator in
which the numerals, plus, minus, multi¬
ply; divide and equals remain relatively
uncluttered. It is therefore appropriate
for use by people who want it only for
simple tasks. , . ,
However, a percentage key provides
a direct mark-up or discount facility for
sales counter use, while a "constant key
offers another approach to problems, ay
For mathematical tasks as such, chain
and mixed calculations are possible, with
multi-function keys to provide square
root, square and reciprocal. The decima^
point is fully floating and, when overload
occurs, the calculation is not lost; press¬
ing the C button once shifts the decimal
point eight places to the right, conserving
the most significant digits.
There is also a memory function con¬
trolled by four keys: M + , M-, MR, MC
and MEX.
The 8 digit display is a bright red,
clearly visible in full room lighting. The
digits are optically enlarged by the bezel
to an equivalent of about 4mm, with the
one disadvantage that they are clearly
visible only to the person using the
calculator.
The sample submitted for review was
accompanied by a simple folder explain¬
ing its main functions. It was intended to
operate with a 9-volt "transistor" style
battery (or external supply) and drew
12.5mA at switch-on, building to 35mA
as "8" numerals were displayed.
Advertised base price of the 95SL cal¬
culator is $9.95 (not including battery) to
which must be added $2.50 to cover mail
order handling and postage.
The 95SC "Scientific" pocket calcula¬
tor is similar in appearance but has 8
digits plus a 9th position to indicate sta¬
tus Optical magnification would appear
to be less, making the digits appear
slightly smaller and sharper. A 9V battery
is specified, again with access for an
alternative supply. Quiescent current
was measured at 20mA, rising to 40mA
with all digits energised, but falling back
to 20 when the automatic fade-out
operates.
While intended primarily for those
needing a mathematical facility, the 95SC
can be used in a simple 4-function arith¬
metic role, by ignoring the secondary
markings. However, it does not have a
direct percentage or "constant" facility,
requiring the informed user to arrive at
the same answers by a slightly more
devious route.
As will be apparent from the pictures
and the advertisements, all keys have a
dual function and, nowadays, likely users
of this type of calculator will be able to
judge their suitability for a particular role
by examining the key notations.
Perhaps the surprising thing about the
95SC is its price: a base figure of $14.99
Above: the 95SL. Below: the 95SC.
(not including battery) to which must be
added $2.50 for mail order handling and
postage. Packaged with the calculator is
a small instruction booklet.
Both calculators are being offered
through the Reader Service Dept of our
parent company )ohn Fairfax Ltd, phone
(02) 20-944 Ext 303. They are obtainable
only by mail order, details being given in
advertisement elsewhere in this issue.
POWER POINT SAFETY TESTER
minimiRFS RISK OF ELECTRIC SHOCK AND APPLIANCE
DAMAGE IDEAL FOR CHECKING OUTLETS IN OLDER HOMES.
INVALUABLE FOR ELECTRICIANS, SERV1CE AND HANDYMEN.
PLUG IN THE POWER POINT SAFETY TESTER AND IMMEDI¬
ATELY SEE IF YOUR OUTLET IS SAFELY WIRED.
swann ciccTRomci ptv ito
Cnr Forster and Hardner Roads, Mt. Waverley, 3149
P.O. Box 350, Mt. Waverley, 3149
Telephone 544 3033. Telex 31707
ELECTRONICS Australia, December, 1976 121
Sprinted circuit?
• Accurately machine printed /etched
• Phenolic & fibreglass-gold /tin plated
• Special manufacturers packs of 10
• EA. R & H, ET. Philips, Mullard available
• Specials to your drawing
•.POSTAGE small 60c. large $1.00
2.00 ET449
2.20 ET448
2.20 ET068
2.00 ET043
2 50 ET711D
2.50 76PC9
6.50 ET446
2.50 ET553C
7.50 ET543B
2.50 ET241
- ET541
2.50 76M17
3.00 76SW4
2.50 76VG5
5.00 76M5
2 50 ET740A
2.50 ET707A
2 50 ET130
2.50 78A03
3.1
2.20 ET804
2.80 ET711C
2.00 ET061
2 00 76MI9
6.00 ET447
4 40 76EX10
2.50 ET533A/C
2.00 ET533A
2.50 ET543A
2.80 ET780B
2 50 ET444
2.50 76LM5
2.00 76R4
5.00 76E04
2.50 76R4
4 50 ET740B
2 50 ET707B
2 50 76RT3
2.50 76G3
5 50 75SWILA/Bpr4 .00 DRSRC1
2 50 EA78F1 2.80 ET534
2.80
2.00
2.80
2.80
2.50
2.50
2.50
3.00
2.50
3 50
2.50
3.00
2 50
4.00
2 50 ET129
3 00 ET420G
2 50 ET119
2 50 ET438
2 80 ET 1 1 24
2 50 75PC12
2 50 FT118
2.50 ET500
3 00 75C07
2 50 ET28
2.50 ET123B
2 60 75F2
2.50 75V12
2 50 ET 1 22
2.50 ET121
2.50 ET117AB
2 50 75T19
2.50
3 00
ET064
ET448A
ET711B
ET044
ET711R
ET544
ET602
ET446
ET711
ET445
ET780A
76SA7
76SS6
76M5
76VG5
ET708
ET514
ET706
76T2
76E02
75PC12
ET514
ET439
ET123A
75111
75F12
, 75CL9
ET120
ET704
75R7
75TU10
75TU9
ET400
ET5298
ET601R
75EM6
ET414E
ET314
E8K1
7501
74MX12B
ET527
ET530
74MX8
ET429
ESP
ESA
E8C
ET424
ETI14
ET601L
ET601J
ET521B
74A1
' ET601D
ET4200
ET524
ET601F
73TU11
73C12
ET419
ET309
73S6
ET416
733C
ET414B
72SA9M
72S11
721 IT
72C8
72R9
72MX6
721F6
PORTABLE AMPLIFIER
«*"** 3%"H * 8'/;"D 12- 16V two inputs. 5 &
lOOmV. 15 ohm output No 763D Also 125 250
500 ohm output No 763A All $70 each. For 240V
I operation $33 extra. Freight collect
COILS and IF's aii 12.50 •• plus post 60c
RF CHOKES Pius post 80c
381 AIR 2 5mh 50ma-Pye 70c.
381 IRON 1 0uh to I .OOOuh 25ma 70c.
! FILTERS 2 7 Line filter 2 Amp $14
L°lusPost$i SO 29 Lme hher 10/20 amp $37.50.
A^lus Post $ 1 50 30 Plj|se f(|ter 2 amp t , 2
MAIL cheque or money order
(add postage) direct to —
RCf radio ply lid
651 FOREST RD BEXLEY
NSW 2207 587 3491
3 50
75FE5
2 50
75TU8
5.00
3.50
ET533A-B
2 50
ET440
4 50
250
75W3
2.50
ET532
2 50
3 30
ET529A
4 50
ET702
2 50
260
ET801P
2 50
E8SRT
3 00
250
75SD4
2.50
75A01
2 50
2 50
ET41402
3 20
ET430
2.50
2 50
ET116
2 50
ESS
3 00
3 00
ET528
2 50
ET312
3 00
2 50
74MX12D
3 50
74MX12C
2.60
3 20
74MX12A
2 60
ET701
2 50
2 50
ET428
280
ET313
2.50
2.50
ET427
2 50
ET428
2 50
2 50
74EM9
2 50
74TU8
250
2.50
E8X
5.00
E810T
500
5 00
E8M
500
E80
5.00
5 00
E8T
5.00
E8F
6 00
600
74C9
420
7408
400
250
ET311
2 50
ET526
2 50
2.50
74SA5
400
ET601M
2 50
250
ET422
3 30
74S3
2 50
3 00
ET423
2 50
ET420E
3 30
2 50
ET601H
2 50
ET601G
2.80
2.50
74MPI
2 50
7312T
2 80
2 SO
ET801C
2 80
ET420C
2 50
2 50
ET420B
2 80
ET420A
2 50
2 80
ET601B
330
ET 60 1 N
3 90
2 80
ET601E
3 90
ET601A
3.30
2 80
73P11
2 80
ET520A-B
4 40
4 90
73BA9
2.80
ETI13
3.10
2 50
ET218
3 50
ET417
2 50
2 80
ET414D
2 50
73TU7
2 80
2 50
ET521
3.90
ET213
2.50
3 30
7301
2 50
ET518
2.50
2 80
73T1
2 80
ET414C
2 80
2 80
ET414A
2 80
72M12
2 80
2 80
ET413
2 80
ET034A
3.10
2 80
72G7
2 80
72110
250
3 30
ET037 40
6 00
72SA10
3.10
2 80
ET029
2 50
72S10
280
2 80
72SA9
2 80
ET033
330
3 10
72T3
3 30
ET026
2 80
2 50
7 1A8
2 50
72P3
2 80
new; easy way
OF DE-SOLDERING ELECTRONIC &
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Simply place Solda-Mop on connection, apply soldering iron
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gauge for 10/20 watt Soldering Irons.
Made by Manufacturers of
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Available from Jacoby Mitchell
and selected Radio and
Electrical Wholesalers.
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OFFICES: Melbourne 44-5021
• Adelaide 293-6117 • Brisbane
52-8266 • Perth 72-2696.
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WIN TV,
PO Box 1800, Wollongong 2500. 28 5444
122
ELECTRONICS Australia, December, 1976
letters to
the editor
Quartz standard
A copy of your review of our Oscillo-
quartz Frequency Standard, published in
the August 1976 issue, was forwarded to
us by our Australian representatives. We
are quite pleased with the generally posi¬
tive presentation given by the author.
However, the article contains some fun¬
damental misconceptions and mistakes
which should be corrected in justice to
your readers.
First, with regard to precision (para. 6).
Since the frequency of the standard can
be adjusted relative to a given reference,
the precision (accuracy) at the moment
of setting the oscillator will be within the
specification for settability, i.e., less than
2 parts in 10E-10. Therefore its later
precision (accuracy) will be determined
by the relative frequency change with the
passage of time.
The time error shown by the 2200
when compared to a standard time refer¬
ence, e.g., atomic time as internationally
defined, will to first order consist of a
time error due to the frequency offset
from the reference, ^nd one due to the
ageing rate of the oscillator times the
square of the elapsed time (see Barnes;
. Proc. IEEE Vol. 54 No. 2, Feb. 1966, pp
207-220). Thus the value quoted by the
reviewer in paragraph 6 is incorrect.
In measuring frequency fluctuations
between two oscillators, it is impossible
to determine the individual characteris¬
tics of either oscillator without a third as
reference. When the 2200 was compared
with the NWC reference using a dual
beam CRO, as described in paragraph 10,
what was the reference? Again there is
a non-precise use of words here, for to
measure a ''frequency drift" of 1 part in
10E-8 is very difficult in a short period of
time.
We hasten to point out that within four
hours after turn-on, 1 part in 10E-8
frequency "drift" of the 2200 for some
undefined measurement interval may not
be so bad at all; nor, for that matter, is
the same order of frequency difference.
We agree with the reviewer that the
result is of dubious validity. When the
2200 oscillator is turned on from a cold
condition, it is quite repeatable in its tran¬
sient frequency characteristics, and this
is confirmed by the reviewer. In fact we
use this characteristic in our model 3200
Cesium Frequency Standard for effecting
the automatic lock capability.
We appreciate the presentation of our
instrument in such an important publica¬
tion in Australia. At the same time we
believe it important for all concerned
that any inaccuracies and incorrect state¬
ments be corrected.
Oscilloquartz, S.A.
Neuchatel, Switzerland.
COMMENT: As you point out yourself,
our reviewer took care to note that limi-
ted time and modest facilities pre¬
vented us from testing the 2200 either
as extensively as it deserved, or when
it had fully stabilised. He also noted that
despite this, its very consistent turn-on
characteristic and the measures of per¬
formance we could take gave every con¬
fidence that it would easily meet its
specs when fully stabilised.
Electronics club
When I arrived in Brisbane as a
transplanted Canadian five years ago, I
was very disappointed at the lack of elec¬
tronic components available. Electronics
shops catering for the hobbyist were few
and far between, and very scantily
stocked. Recently, however, with the
arrival of Dick Smith, Techniparts, Tandy
and others there has been a very wel-
come expansion.
I feel that there is another need to be
filled - an electronics hobbyist's club.
Somewhere members . could gather to
trade circuits, talk electronics and
perhaps use expensive equipment be¬
longing to the club which would be
beyond the finances of individuals. For
a beginner whose new home-built
oscillator refuses to work, a few old
hands within calling range could mean
the difference between going on to big¬
ger and better things in electronics, or
giving it away altogether.
With this idea in mind, I would like to
organise an Electronics Hobby Club here
in Brisbane, and wondered if Electronics
Australia would consider printing my
name, address and telephone number in
order that interested hobbyists could
contact me.
Frank Halliwell
10 Nidalla Street,
Macgregor, Qld- 4109 (Tel. 349-9834)
Protect your
instruments and
equipment with
ALERT
cartridge fuses
ALERT fuses are "on guard"
against electrical overloads in
Electronic, Industrial and
Telecommunications
installations. Manufactured by
Kenneth R. Beswick Ltd., U.K.,
the ALERT range include
British Military Standards,
British P.O. Standards, and
many of the international
specifications.
Popular Sizes EX-STOCK
TDC 10: V/a" x Va" Quick
acting 100 ma to 25
amp.
TDC 11: 1 Va" x Va" Slow blow
(or delay) 60 ma to 10
amp.
TDC 13: 20mm x 5 mm Quick
acting 63 ma to 3 amp
TDC 69: Vs" x 3/16" Quick
acting 25ma to 10
amp.
TDC 123: 20mm x 5mm Slow
blow 100 ma to 2 5
amp.
Available from Wholesalers
or the Australian Agents
VIC.: 493-499 Victoria St., West
Melbourne 3003 Ph.: 329 9633
N S W . 4-8 Waters Rd., Neutral
Bay 2089 Ph. 909 2388
W.A.: 256 Stirling St., Perth
6000 Ph 28 3655
QLD.: L. E BOUGHEN &C0 .
Corner Milton & Baroona Rds .
Milton 4064. Ph : 36 1277
S.A. : Werner Electronic
Industries Pty. Ltd., Unit 25,
28 Gray St . Kilkenny 5009.
Ph 268 2801
Telex. Melbourne, 31 447.
Sydney. 21707. Brisbane.
41500. Perth. 93244
The views expressed by correspondents are
their own and are not necessarily endorsed by
the editorial staff of 'Electronics Australia1.
The Editor reserves the right to select letters on
the basis of their potential interest to readers
and to abbreviate their contents where this
appears to be appropriate.
FI FCTRONICS Australia, December, 1976
jjff synthesised SSB
$245
27MHz *
| This superb rig is the ultimate in quality and sophistication) Th« rnmnn
sswsSi E
[dummy load ^ AC #
i£°Byz7—Ti -
| ££ s«aorv iM ** '" 27 ."2 _
GET THOSE EXTRA “S” POINTS! *
I Popular VC2 swr/pvvr meter operates 3-150 MHz with
' lOOo' wamU 50*ohm2/12° " hand,B UP to
bSStoTiSi” «*•
SWR/PWR METER *
I QUALITY MIC COMPRESSORS
I Increase average 'Talk power ' by
■ connection to the transmitter mic-
■ rophone circuit for sideband
I transmitters-MODEL MC33A ac/dc
■ includes 2 tone generator and built-
■ •" compression level meter.
$65
BUILT-IN SWR BRIDGE!
N£W <140 '
COUGAR 23 B AM DELUX TRANSCEIVER
fee tu res^bu ! It fn qUa',,y «•"**»« Novice. The Cougar
S+N/N, selectivity 6 dB bandwidth 5 kHZ^PA^uZ^v^S w«U JransSiVte*
5w input, spurious harmonic suppression better than 557b watt*k™ANSM'TTER:
Comes complete w,th mic. mobile bracket, dc cable and manual. iV
ANTENNAS FTTH
’/a WAVE HIGH EFFICIENCY GROUND PLANE
Solid heat-treated aluminium construction rugid
terminated to S0239 socket $28.50 + P&P $3 '
27 MHz Helical Ground plane Antenna
A GROUND PLANE WITHOUT HASTLES!
Teflon wire wound on light and strong fibreglass rod
$65 + P&P $3
27 MHz TRUCK ANTENNA
Twin centre loaded mirror mounted antennas es¬
pecially designed for truck use. Comes complete with
cables, plugs, connecting brackets, $34.50 + P&P $3
MODEL Ml 27 MHz MOBILE WHIP
Base loaded stainless-steel mobile
whip, 40.5 inches. 50 ohm
impedance, vswr less than 1.5.
Includes roof-top mount, optional
boot lid mount, spring and coax with
PL259 plug. Tensile strength 260,000
WITH
Superb quality low pass filter (34|
MHz cut-off) will handle up to 1 kW|
pep. 50 ohms impedance with
sertion loss better than 0.3 dB.L
Copper construction with S0239I
sockets. $29
TVIJROBLEMS ? ft
MODEL G2 AS ABOVE
GUTTER CLAMP $24.50
hf trap dipoles «£?
AL48DXN 40 & 80 metres, length **
28 metres 5 40
AL24DXN 20 & 40 metres, length
metres 5 40
MIDY VN 80 thru 10 metres, length
23 metres $48
amateur gear
Rmgo-Ranger ARX2. three half waves
6 dB gamma loop matched vertical $ 40 I
AS210BN 2m beam, twin boom lOel each
boom, 18 dB gain. F/B 20 dB. length 4m
weight 6.8 Kg
HF MOBILE ANTENNAS
AS303A Antenna Set 80 thru 10 metres,
centre loaded, incl heavy duty ball
mount and spring $105 I
Quality Hustler Resonators. Precision
would with optimum design for each
D»HiQn*mr»Stable ,rip rod for swr:
5X metres! i26 RM20 (2° 520
RM40 (40 metres) $25 RM11 (11 metres) $24
BM1 Bumper mount $15 RSS-2 spring $12
lUNIDEN - the bestvalucT
The fabulous UNIDEN 2020 (MK11) PLL transceiver
2?'' “b/lsb/cw 8 pole crystal filters as standard
and 6146B s in the final with screen voltage stabilisation
tor minimum distortion products. Features plug-in pcb's
and even the front panel can be swung out for easy
I servicing. This superbly engineered rig cover 80 thru 10
HL 't VnoTtre$) 3t 180w DC inPut ssb- Compare
the UNIDEN 2020 with other HF transceivers and you'll
be quickly convinced that it offers the best value!
2020 Digital transceiver
| Umden digital VFO
RECEIVERS FOR THE SERIOUS SWL! Sfr
I 27 MHz/CAR RADIO SPLITTER •£ ^
l2Ti?#Ei°n °f V°Ur AM °f AM/FM car radio
V27 antenna. Can be used with any series
|fed (unarcundadl 27 MHz antenna. Finished with
I H and car rad,° h,9h impedance lead each
1 60 inches long. Excellent isolation between enter
I tain men t radio and 27 MHz trans«*vT^nclX
l$26‘ P&P*vmHZ ma,Ch“ ,0r optimising SWR.
27 MHz Helical Ground plane
Wliy ukc the jumble7
All ri,t* v)ld by VICOM arc given |
a thorough pre-delivery checkout L
supported by technical expertise I
and well equipped workshops, f
c parts ate available loo’
Yes, the famous Barlow Wadley
general coverage receiver with
crystel controlled reception of
am/lsb/usb/cw now includes the
Australian FM band!
BARLOW WADLEY
w[?h?mR° f269 + p&p
WITH FM $298 + p&p
The new Yaesu FRG-7 general
coverage receiver features ac/dc
operation and the famous Wadley
Loop principle with spin tuning
and phase-locked synthesiser pro¬
viding complete coverage from
500 KHz to 30 MHz with an
accuracy better than 5 KHz.
Please write for further technical
details (enclosing SAE)
OUR PRICE + P&P
ANTENNAS
] ;V';iVPe antenna-. Covers 3-30 MHz with special
trap. Ideal for DX reception. $21 + P&P
Listener 3 Long Range wire dipole antenna 3-30 MHz
complete with balun. feed wax. VHF plugs, insulators
P&P _ _
ICOM
IC215 HANDY FM PORTABLE
This i, ICOM's first FM portable, and it puts
good times on the go. Change vehicles, walk
through the park, climb a hill, the ICOM
quality FM communications go right along
MOU ch°n9 l.fS,in9 internal batteries make
portable FM really protable, while accessible
teatures make conversion to external power
fast and easy!
* Fully collapsible antenna
* 15 channels (12 on dial + 3 p.ior.tv)
Dual power 3 watts/40 mW
* Lighted dial and meter $164
Crystals same as IC22 series
Your new IC215 comes complete with 3
popular channels, mic, shoulder strap
VirnMcn'w bWt>ri“' En«lish Manual and
VICOM 90 day warranty.
quality handy portables
The famous IC202 handy portable runs 3
watts pep with VXO control 144 146 MHz
Features noise blanker, RIT, lighted dial and
meter, telescopic antenna and of course that
ICOM quality) Comes complete with mic
carrystrap. dry cells, English manual and
90 day warranty.
IC502 sits IC202 $185
Six metres SSB using the IC502 can be great
i Portable runs 3 watts pep
ssb 52-53 MHz. Featuring VFO control, suitch-
cable noise blanker, RIT and provision for
external power and speaker, 9 long-life C
batteries, English manual and 90 day warranty
... where quality counts!
SYNTHESISED!
NO CRYSTALS
IC22S $220
The new IC22S transceiver is a PLL synthesised
rig with programmable ROM for any frequency
multiple of 25 KHz from 144 to 148 MHz.
Simplex, duplex or reverse achieved by a flick
of a switch on the front panel. This fabulous
new rig features ceramic discriminator, I DC
vIcoJ?'L77RX relaV' fu" *Wf Potion and
VICOM 90 day warranty. Circuitary includes
34 transistors. 7 FETs, 13 ICs and up to 128
?" °d” Reiver sensitivity better than 0.4 uV
tor 20 dB quieting. Your new IC22S comes
complete with mic, mobile mounting bracket
Plugs cables, spare diodes for programmable
matrix and English Instruction Manual.
„ and sockets for the!
COMMUNICATOR!
(minimum mail order $5)
259 plugs with reducer ^ k ^ $i .20 I
S0239 chassis socket " $1^20 1
S0239/PL259 tr angle connector $1 .95 J
S0239 3 female ”T” adapter $2.00 1
"T" connector $2,201
Solderless in-line splice .90 |
18” coax jumper lead with PL259s $2!oO I
**' coax jumper lead with PL259s $2.20 I
pin mic plugs and sockets $1 .90 I
pin mic plugs and sockets $1 .90 I
RG58A/U 52 ohm coax - 45c/metre
RG8 low loss coax - 45c per foot
' ” W aay warranty. . . .
1 _ . . . ' — RG8 low loss coax - 45c per foot
>he COMMUNICATIONS SPECIALISTS!
Cables & Telegrams "IZYCOM" Melbourne
UfcALtKb
Perth.
Canberra:
Head Office & mail orders . .
139 Auburn Rd, Auburn, Vic. 3123 Ph: (03) 82-5398
Sydney Branch . . .
23 Whiting St, Artarmon, NSW 2064 Ph: (02) 439-1271
Netronics. 338 Huqtriss Ave, Woodlands Ph 46 3232
ra The Electronics Shop (Daicom), 29 Colbee Court
Phillip. Phone 82 3581
le Graham Stallard. 27 White Ave, Lockleys, Ph 437981
e: Elite Electonrics. 69 Warded St, Dorrmgton. Ph 38 4480
Prices and specifications subject to
change without notice. Prices include
Sales Tax but exclude freight and
Insurance. Allow 50c per $100, minimum $1
124
ELECTRONICS Australia, December, 19 76
The Amateur
Bands
by Pierce Healy, VK2APQ
Contact:
Club name:
Club call sign:
Meeting place:
Day and time:
Affiliation:
Net frequency:
Australian radio clubs
Contact:
In presenting this year's list of amateur radio clubs we express the hope ^ name.
that it will benefit both the clubs and individual readers. Readers who
wish to further their knowledge of amateur radio and electronics are
advised to look up their nearest club and attend the next meeting. You jjbgjjgj
will be most welcome.
Club name: WIA, ACT DIVISION - CAN¬
BERRA RADIO SOCIETY.
Club call sign: VK1WI, VK1ACA, VK1RAC.
Meeting place: The Studio, Griffin Centre,
Bunda Street, Civic, ACT.
Day and time: Fourth Monday of each
month at 8.00pm.
Affiliation: Member of the Wireless
Institute of Australia.
Net frequency: Channel 6 repeater VK1RAC,
Channel 50 & 7050kHz.
Contact: Secretary Mike Vale,
VK1VW, PO Box 1173, Can-(
berra City, ACT 2601 .
Club name: HUNTER BRANCH NSW
DIVISION WIA.
Club call sign: VK2AWX; repeater channel 6
VK2RAN.
Meeting place: Newcastle Technical College
and Northumberland Radio
Centre, Teralba.
Day and time: First Friday of each month at
NTC and third Friday of each
month at NRC.
Net frequency: 3570kHz each Monday night
at 7.30pm.
Contact: Secretary, Ray Leban, PO Box
134, Charlestown. Bill Hall,
VK2XT, telephone 59 1586.
Club name: CENTRAL COAST AMA¬
TEUR RADIO CLUB.
Club call sign: VK2AFY.
Meeting place: Clubrooms, Dandaloo Street,
Kariong.
Day and time: First and Third Friday of each
month 8.00 pm.
Affiliation: WIA NSW Division.
Net frequency: Channel 3 repeater
VK2RAG.
Contact: Mrs S. J. Wells, PO Box 238,
Gosford, NSW 2250.
Club name: WAGGA DISTRICT RADIO
CLUB.
Club call sign: VK2WG.
Meeting place: Wagga Rescue Club Rooms,
Bolton Street, Wagga.
Day and time: Last Friday of each month at
8.00pm.
Affiliation: WIA NSW Division.
Net frequency: Channel 3 repeater
VK2RWG.
Contact: Secretary Frank Sleep, PO
Box 71, Koringal, Wagga
2650.
Club name: ILLAWARRA AMATEUR
RADIO SOCIETY.
Club call sign: VK2AMW.
Meeting place:
Day and time:
Affiliation:
Net frequency:
Contact:
Club name:
Club call sign:
Meeting place:
Day and time:
Affiliation:
Net frequency:
Contact:
Club name:
Club call sign:
Meeting place:
Day and time:
Affiliation:
Net frequency:
Contact:
Club name:
Club call sign:
Meeting place:
Day and time:
Affiliation:
Net frequency:
Wollongong Town Hall
Meeting Room.
Second Monday of each
month at 7.30pm.
WIA NSW Division.
Channel 5 repeater
VK2RAW.
President Ian Bowmaker,
VK2ZJA, PO Box 1433, Wol¬
longong 2500, telephone 29
2158 or Keith Curie,
VK2BUU, 24 Beach Drive,
Woonona 2517, telephone 84
2469.
ORANCE AND DIS¬
TRICT AMATEUR RADIO
SOCIETY.
VK2AOA.
Orange Technical
College.
Every Friday night
7.00pm.
WIA NSW Division.
Channel 2 repeater
VK2AOA/R.
Pres. Robert Alford,
VK2ZRJ, telephone
62 1544 (Bus), 62 4673
(AH), Secretary Allan
Wright, VK2BVL,
telephone 62 1432.
OXLEY REGION RADIO
CLUB.
VK2BOR.
As convenient to mem¬
bers.
As convenient to mem¬
bers
NSW Division WIA.
Club channel 2 repeater.
Peter Alexander, VK2PA,
PO Box 152, Port
Macquarie, NSW 2444,
telephone (065) 83 2033.
WAVERLEY RADIO
CLUB.
VK2BV.
1/6 Blenheim Street,
Bondi Junction, or venue
advised in VK2WI news
broadcasts 11.00am and
7.30pm Sundays.
Second Thursday each
month at 8.00pm.
WIA NSW Division.
Channel 6 repeater
VK2RBV.
Day and time:
Affiliation:
Net frequency:
Contact:
Club name:
Club call sign:
Meeting place:
Day and time:
Affiliation:
Contact:
Club name:
Club call sign:
Meeting place:
Day and time:
Affiliation:
Net frequency:
Contact:
Club name:
Club call sign:
Meeting place:
Day and time:
Affiliation:
Net frequency:
Contact:
ELECTRONICS Australia,
Secretary Phil Card,
VK2ZBX, telephone (AH)
389 3035, (Bus) 663 0193.
ST. GEORGE AMATEUR
RADIO SOCIETY.
VK2LE.
Civil Defence Head¬
quarters, Highgate Street,
Bexley.
First Wednesday of each
month 7.30pm.
WIA NSW Division.
Channel 4 repeater
VK2RLE, Thursday
8.00pm, 14.1MHz VK2LE,
Thursday 7.30pm
The Secretary, SCARS, PO
Box 77, Penshurst 2222.
HORNSBY & DISTRICT
AMATEUR RADIO
CLUB.
VK2APF.
Waitara Scout Hall,
Palmeston Road,
Hornsby.
Second and fourth Wed¬
nesday each month
8.00pm. 4
WIA NSW Division.
146.55MHz FM; 3.56MHz,
Mondays 8.00pm.
Kurt Lass, VK2YCU,
telephone 48 1426.
BLUE MOUNTAINS
RADIO CLUB.
VK2AUX.
Springwood Primary
School and Blaxland
Primary School.
Every Friday night 8.00pm
at SPS and first Monday of
each month 8.00pm at
BPS.
Blue Mountains Branch,
WIA NSW Division-.
Peter Willis, telephone
39 2203 or Geoffrey Swift,
telephone 39 1144.
UNIVERSITY OF NSW
AMATEUR RADIO
CLUB.
VK2BUV.
Room 1 or 2, 2nd floor,
Student's Union Stage 3
building.
First Thursday of each
month at 1.00pm.
WIA YRCS NSW.
27.125MHz.
The Union, Box 57, PO
Box 1, Kensington 2033,
or Sam Voron, VK2BVS, 2
Griffith Avenue, Roseville
2069, telephone 407 1066.
NOVICE AMATEUR
RADIO GROUP.
VK2BNO.
Wireless Institute Centre,
14 Atchison Street, Crows
Nest.
Every Saturday afternoon
2.00pm-5.00pm.
WIA Youth Radio Club
Scheme.
27.125MHz each Sunday
at 11.00am and 7.30pm.
WIA NSW Division News
Broadcast.
Brian Belcher, 73 Ernest
Street, Crows Nest,
telephone 43 5632.
December, 1976 125
AMATEUR BANDS
Club name:
THE SYDNEY DX
GROUP.
Club call sign:
VK2BDX.
Meeting place:
Wireless Institute Centre,
14 Atchison Street, Crows
Nest.
Day and time:
First Friday each month at
7.30pm.
Affiliation:
WIA Youth Radio Club
Scheme.
Net frequency:
27.125MHz 8.15pm each
Sunday then QSY to
27.085MHz.
Contact:
Roger Brown, VK2BEQ,
18 Bradleys Head Road,
Mosman 2088, telephone
969 2487.
Club name:
WESTLAKES RADIO
CLUB.
Club call sign:
VK2ATZ.
Meeting place:
Club Rooms, York Street,
Teralba.
Day and time:
Each Saturday afternoon
Affiliation:
and Wednesday evening.
WIA and YRCS NSW
Division.
Net frequency:
Not stated.
Contact:
Eric Brockbank, VK2ZOP,
Secretary, PO Box 1,
Teralba, NSW 2284. Club
telephone 58 1588.
Club name:
SYDNEY UNIVERSITY
AMATEUR RADIO
CLUB.
Club call sign:
VK2BSU.
Meeting place:
Check WIA broadcasts or
Uni "Daily Bull".
Contact:
Jeff Pages, VK2BYY,
telephone 649 9829 or
write to Box 398, Went¬
worth Building, Sydney
University 2006.
Club name:
CAMPTEC (Camp Tech¬
nology). .
Club call sign:
VK2BCT.
Meeting place:
"The Grange", Mt. Vic¬
toria, NSW.
Day and time:
Three one week residen¬
tial camps each January.
Affiliation:
YRCS NSW.
Net frequency:
14MHz and 146MHz and
operation on other
bands.
Contact:
Mr J. Wightman, 10/37
Eddystone Road, Bexley,
NSW 2207.
Affiliation:
Net frequency:
Contact:
Club name:
Club call sign:
Meeting place:
Day and time:
Affiliation:
Net Frequency:
Contact:
Club name:
Club call sign:
Meeting place:
Day and time:
Affiliation:
Net frequency:
Contact:
Club name:
Club call sign:
Meeting place:
Day and time:
Affiliation:
Net frequency:
Contact:
Club name:
Club call sign:
Meeting place:
Day and time:
Affiliation:
Net frequency:
Contact:
Club napie:
Club call sign:
Meeting place:
Day and time:
WESTERN SUBURBS
RADIO CLUB.
VK2BWS.
Scout Hall, Cnr. Fowler
and Kenyons Roads, Mer-
rylands, NSW.
Second and fourth Tues¬
day of each month at
8.00pm.
WIA NSW Division.
Nil.
Peter Gosling, 14 Clarke
Street, Berala, 2141.
MOORABBIN AND DIS¬
TRICT RADIO CLUB.
VK3APC.
Club Rooms, Turner
Road, between Nepean
Highway and Chesterville
Road, Moorabbin.
Third Friday of each
Club name:
Club call sign:
Meeting place:
Day and time:
Affiliation:
Net frequency:
Contact:
Club name:
Club call sign:
Meeting place:
Day and time:
ELECTRONICS Australia, December, 1976
month at 8.00pm.
WIA Victorian Division.
Nil.
Secretary Graham Mason,
VK3YGM, 3 Mason Court,
Highett 3190, telephone
95 8108.
EASTERN AND MOUN¬
TAIN DISTRICT RADIO
CLUB.
VK3ER and VK3BNW.
General meetings in the
Willis Room of the library.
Branch meetings in the
Coffee Shop, Nunawa-
ding Civic Centre,
Maroondah Highway,
Nunawading.
General meeting first
Friday of each month and
Branch meeting fourth
Friday of each month
commencing at 8.00pm.
WIA Victorian Division.
3660kHz each Monday at
8.00pm.
Secretary Bob Duck¬
worth, VK3AIC PO Box
87, Mitcham, Vic. 3132,
telephone 725 8656.
WESTERN SUBURBS
RADIO CLUB (VrC-
TORIA).
VK3AWS.
Recreation Room, Mel¬
bourne Caravan Park, 263
Elizabeth Street, East
Coburg.
First and Third Friday
each month (except
January) at 8.00pm.
Not stated.
Not stated.
Secretary Reg Loyd,
VK3KK or publicity officer
Robert Ayton, VK3WS.
GEELONG AMATEUR
RADIO & TV CLUB.
VK3ATL.
Club Rooms, Storrer
Street, East Geelong.
Each Friday night at
8.00pm.
WIA Victorian Division.
Channel 8 repeater
VK3RGL.
Secretary, PO Box 520,
Geelong 3220, or Alan
Bradley, VK3LW,
telephone 43 7550.
GEELONG RADIO AND
ELECTRONICS SOCIETY.
VK3ANR.
Club Rooms, Recreation
Reserve, Breakwater
Road, Belmont, Victoria.
Not stated.
Not stated.
Not stated.
M. G. Hepner, Secretary,
PO Box 962, Geelong,
Victoria 3220.
WARRNAMBOOL AMA¬
TEUR RADIO CLUB.
VK3ASZ.
Buffalo Lodge Rooms,
Kariot Street, Wannam-
bool.
First and third Wednes¬
day of each month at
8.00pm.
Affiliation:
Net frequency:
Contact:
Club name:
Club call sign:
Meeting place:
Day and time:
Affiliation:
Net frequency:
Contact:
Club name:
Club call sign:
Meeting place:
Day and time:
Affiliation:
Net frequency:
Contact:
Club name:
Club call sign:
Meeting place:
Day and time:
Affiliation:
Net frequency:
Contact:
Club name:
Club call sign:
Meeting place:
Day and time:
Affiliation:
Net frequency:
Contact:
Club name:
Club call sign:
Meeting place.
Day and time:
Affiliation:
WIA Victorian Division
South West Zone.
Not stated.
Ian Mason, PO Box 10,
Yambuk, Vic. 3285,
Publicity Officer.
LARA - LADIES' AMA¬
TEUR RADIO ASSOCIA¬
TION.
Nil.
As arranged each month
in Melbourne. Other
locations to be organ¬
ised.
As suitable to members.
WIA State Divisions.
3650kHz each Monday
evening at 8.00pm.
LARA (Australia), C/-412
Brunswick Street, Fitzroy,
Vic. 3056.
GOLD COAST RADIO
CLUB.
VK4WIG.
Surfers Paradise old state
school.
First Friday of each month
at 7.30pm.
WIA Queensland
Division.
Channel 2 repeater
VK4RGC, Sunday evening
7.30pm and 3565kHz or
3650kHz Sunday evening
at 8.00pm.
Secretary, PO Box 588,
Southport, Qld. 4215.
CENTRAL QUEENS¬
LAND BRANCH - WIA
QLD, DIVISION.
VK4WIR.
Adult Education Rooms,
Technical College,
Rockhampton.
Third Friday of each
month at 7.45pm.
WIA Queensland
Division.
FM Channel 50, repeater
VK4RAR channel 4.
Secretary, PO Box 496,
Rockhampton, Qld. 4700,
Doug Kraatz, VK4ZDK,
telephone 28 2533.
DARLING DOWNS
RADIO CLUB.
VK4RDD repeater.
Toowoomba Education
Centre, Baker Street,
Darling Heights,
Toowoomba.
Last Friday of each month
(except December) at
7.30pm.
WIA Queensland
Division.
Channel 4 repeater
VK4RDD.
Secretary, 241A 1
McKenzie Street,
Toowoomba, Qld 4350.
IPSWICH AND DISTRICT
RADIO CLUB.
VK4WIP.
Club Rooms, Deebing
Street, Denmark Hill,
Ipswich.
Every other Tuesday
evening, at 7.30pm.
WIA Queensland
Division.
Net frequency:
Contact:
Club name:
Club call sign:
Meeting place:
Day and time:
Affiliation:
Net frequency:
Contact:
Club name:
Club call sign:
Meeting place:
Day and time:
Affiliation:
Net frequency:
Contact:
Club name:
Club call sign:
Meeting place:
Day and time:
Affiliation:
Net frequency:
Contact:
Club name:
Club call sign:
Meeting place:
Day and time:
Affiliation:
Net frequency:
Contact:
Club name:
Club call sign:
Meeting place:
Day and time:
Affiliation:
Net frequency:
Repeater VK4RAI channel
6.
Secretary, PO Box 250,
Ipswich, Qld. 4305.
QUEENSLAND BRANCH
HQ BOV SCOUTS
RADIO CLUB.
VK4QH.
Baden Powell Park, Sam-
ford.
First Sunday of each
month at 9.30am to
I. 00pm.
W I A Queensland
Division.
7070kHz 9.30am to
II. 00am and 14.290MHz
11.00am to 1.00pm each
Sunday.
Noel Lynch, VK4ZNI, 15
Noeline Street, Dorring-
ton, Qld. 4060.
WINDSOR YMCA.
RADIO CLUB.
VK4AYM.
Windsor YMCA, 387 Lut-
wyche Road, Windsor,
Brisbane.
Each Friday 7.00pm-
9.00pm.
YMCA and WIA
Queensland Division.
3570kHz AM, 3530kHz
CW, 27015kHz CW,
27125kHz SSB.
Roger Davis, telephone
356 9228 or Geoff
Adcock, telephone
59 7332
THE BRISBANE VHF
GROUP.
VK4IF.
Oakleigh Scout Den,
High Street, Dorrington.
Fourth Thursday of each
month at 8.00pm.
WIA Queensland
Division.
Channel 8 repeater
VK4RBN.
A.Downie,VK4ZRF,23
Vanburgh Street, Mt
Gravatt, Qld. 4122.
BUNDABERG AMATEUR
RADIO CLUB.
VK4BW.
Club Rooms, Avoca
Street, West Bundaberg.
First Wednesday of each
month at 7.30pm.
WIA Queensland
Division.
Repeater in planning
stage.
Secretary, PO Box 129,
Bundaberg, Qld. 4670.
REDCLIFFE RADIO
CLUB.
VK4RC.
Congressional Church
Hall, Cnr. Elian and Alfred
Streets, Woody Point.
Every Monday evening
(except school holidays)
at 7.30pm.
WIA Queensland
Division.
3655kHz Sunday evening
at 7.45pm and 14.3MHz
Sunday evening at
8.00pm.
Contact:
Club name:
Club call sign:
Meeting place:
Day and time:
Affiliation:
Net frequency:
Contact:
Club name:
Club call sign:
Meeting place:
Day and time:
Affiliation:
Net frequency:
Contact:
Club name:
Club call sign:
Meeting place:
Day and time:
Affiliation:
Net frequency:
Contact:
Club name:
Club call sign:
Meeting place:
Day and time:
Affiliation:
Net frequency:
Contact:
Club name:
Club call sign:
Meeting place:
Day and time:
Affiliation:
Net frequency:
Contact:
Club name:
Club call sign:
Meeting place:
Secretary, PO Box 20,
Woody Point, Qld. 4019.
MARYBOROUGH AMA¬
TEUR RADIO CLUB.
VK4WIB.
Old Boys School, Sussex
Street, Maryborough.
Every Monday evening at
7.45pm.
WIA Queensland
Division.
FM channels 40 and 50.
Col Paton, 225 Pallas
Street, Maryborough,
Qld. 4650.
MACKAY AMATEUR
RADIO CLUB.
Vk4WIM.
13 Boundary Street,
Mackay.
Fourth Friday of each
month at 8.00pm.
WIA Queensland
Division.
FM channel 50 Thursday
evening 8.00pm.
Secretary, PO Box 1065,
Mackay, Qld. 4740.
TOWNSVILLE AMATEUR
RADIO CLUB.
VK4WIT.
State Emergency
Headquarters, Green
Street, West End, Towns¬
ville.
First Thursday each
month 8.00pm.
WIA Queensland
Division.
53.032MHz Sunday
11 .00am, 3605kHz Sunday
evenings 7.45pm, Chan¬
nel 2 repeater VK4RAT.
Secretary, PO Box 964,
Townsville 4810.
Day and time:
Affiliation:
Net frequency:
Contact:
Club name:
Club call sign:
Meeting place:
Day and time:
Affiliation:
Net frequency:
Contact:
Club name:
Club call sign:
Meeting place:
Day and time:
Affiliation:
Net frequency:
Contact:
O'Sullivan Beach, Sth.
Aust.
Tuesday and Thursday
nights, 7.00-9.30pm.
Not stated.
3530kHz and 27.085MHz.
Nick Mclean, VK5NIC 33
Kentwood Rd, Morphett
Vale Sth. Aust. Phone
382 5472.
WEST AUSTRALIAN VHF
GROUP (INC.)
VK6WH & VK6VF/P.
Group Headquarters.
Wireless Hill Museum,
Cnr. Almondbury Road
and McCallum Crescent,
Ardross, WA.
Fourth Monday of each
month ( December
excluded) at 8.00pm.
WIA West Australian
Division.
All two metre FM chan¬
nels monitored.
T. C. Berg, VK6ZAF, 23
Beach Road, Bicton 6157,
telephone 39 3614 (AH),
80 2749 (Bus). Postal: PO
Box 189, Applecross, WA. ^
6153.
WAIT AMATEUR RADIO
CLUB.
VK6PD.
Cultural Centre, West
Aust. Inst, of Technology
(WAIT).
Wednesday 1.30pm —
5.00pm; 7.30pm —
10.30pm.
Not stated.
14.170MHz daytime and
evening, 3685kHz even¬
ings.
Interclub Comm. Rep.
Gill Weaver, VK6ZGI.
*
CAIRNS AMATEUR
RADIO CLUB.
VK4HM.
State Emergency Service
Building, McNamara
Street, Cairns.
Second Wednesday of
each month at 8.00pm
WIA Queensland
Division.
FM channel 50 moni¬
tored.
Secretary, PO Box 1426,
Cairns, QLD. 4870.
ELIZABETH AMATEUR
RADIO CLUB.
VK5LZ.
Methodist Church Hall,
Fairfield Road, Elizabeth
Grove, Sth. Aust.
First Saturday of each
month at 8.00pm.
WIA South Australian
Division.
Nil.
Secretary, PO Box 8,
Elizabeth, SA 5112, or
president Ted Cooling,
telephone 255 2249;
255 7586 or publicity
officer Bill Thomas,
telephone 258 6070.
SOUTH COAST RADIO
AMATEURS GROUP.
Not stated.
Baden Terrace,
Club name:
Club call sign:
Meeting place:
Day and time:
Affiliation:
Net frequency:
Contact:
DARWIN AMATEUR
RADIO CLUB.
VK8DA.
Northern Territory Emer¬
gency Services Building,
Bishop Street, Winnellie.
First Monday of each
month at 8.00pm.
South Australian Division
WIA.
Channel 50 (145.5MHz),
3555kHz.
Henry Andersson,
VK8HA, PO Box 1418,
Darwin. Telephone
81 8587.
SO YOU WANT TO BE
A RADIO AMATEUR?
To achieve this aim, why not undertake one
of the Courses conducted by the Wireless
Institute of Australia? Established in 1910
to further the interests of Amateur Radio,
the Institute is well qualified to assist you
to your goal. Personal Classes for 1977 will
commence on Tuesday, February 8th.,
1977. Applications which are accepted in
order of priority, are now being received.
Correspondence Courses may be com¬
menced at any time.
For further information, write to
THE COURSE SUPERVISOR,
W.I.A.
14 ATCHISON STREET,
CROWS NEST, N S W. 2065
ELECTRONICS Australia, December, 1976
127
E1ESTPBE1I3S
specials
Supply Sariha
179 VICTORIA ST., KINGS CROSS N.S.W. 201 1
proportional radio control
TRANSMITTER-MODULATOR
TXM Module. ..$13.50
Kit. ..$11.50
27MHz . crystal controlled transmitter
-modulator. Requires antenna*, crystal
and 12 volt supply. Typical range is
100 metre, output is 300mW. Input is
suitable for Amplitude modulation.
RECEIVER
RX Module. . .$13.50
Kit. ..$11.50
27MHz. crystal controlled receiver. A
9 volt supply, antenna and crystal is
required. This receiver uses a ZN414
integrated circuit chip, and an IF of
455kHz .
CRYSTALS
I XT2 Pair. . . $ 6.95
A matched pair with 455KHz separation
ENCODER
EN15 Module. . .$13.50 Kit. ..$11.50
15 channel proportional encodfer. This
is a pulse width modulation type with
synchronisation. It requires a 5 volt
supply, and can directly drive a TXM
module. All channel positions are set
by 10k potentiometers, these are not
supplied with the module or kit. This
encoder can easily be converted to a
system with fewer channels.
DECODER
DC15 Module. . .$13.50
Kit. ..$11.50
I 15 channel proportional decoder with
synchronisation. It requires a 5 volt
supply and is driven directly by the
receiver module. Servo and drive unit
will be featured in a later issue.
printed circuit boards
Boards required for building EA and ET
projects will be available about one
week from issue of, the magazines. Also
boards can be made to your artwork. In
I both cases the cost will be...
Single side laminate.'. basic 80c
per square inch 5c
Double side laminate.. basic 90c
per square inch 9c
| Single side fibreglass.. basic 8
per square inch
| Double side fibreglass.. basic 9
per square inch 1
'formers -ferrites
I Ceramic Resonators
SFD455B
SFB455A
BFB455A'
I YFL455A
Coils
S201
S.203
ST45C
5195
5196
S500
90pF oscillator coil
200pF aerial coil
455kHz IF coil
Rf bandpass
Rf bandpass
Minature Osc, 3 x IF set
$1.20
80c
80c
$2.50
$2.95
$2.95
$2.95
$2.95
$2.95
$2.50
Crystals
I 2MHz HiQ type.
Slugs and Cores
F16 4mm to 15MHz.
F29 4mm to 300MHz.
500 6mm to 10MHz. *
900 6mm to 60MHz.
901 6mm to 200MHz.
910 6mm to 300MHz.
Ferrite Cores
| FX1115 Ferite bead
»6 2242 replacement potcore
0 2243 replacement potcore
2 E core and former
•* Large potcore for ETI427
* Small potcore for ETI427
* state uE values required
$8.75
15c
$2.75
$4.50 I
$2.90
$2.80 [
$2.30
I Coil formers
722/1 5mm x
722/4
5 000 A
5000B
6PLB
7100
7101
DTV2
DTV1
5mm x
7mm x
7mm x
722 base
722/1 can
722/4 can
5000A can
5000B can
14mm former
33mm former
34mm former
61mm former
I layout aids
I PR12 50ml positive photo resist
$3.95
I PD16 80gm positive developer
$1.75
1 DPB Dalo resist pen
$2.38
1 FCA 500gm ferric chloride
$1.95
1 LF1 100ml liquid flux
$1.54
I T04 20 yd .04 black tape
$1.60
I T08 20 yd .08 black tape
$1.60
I T06 20 yd .06 black tape
$1.60
1 D100 88 .lx .031 donut
$1.45
D156 88 .156 x .031 donut
$1.45
T018 18 group of 3 leadouts
$1.45
T05 18 group of 8 leadouts
$1.45
DIL14 16 groups of 14 pinouts
$1.45
DIL16 16 groups of 16 pinouts
$1.45 I
AFG Sheet with .1 grid layout
65c 1
XOB pack of five exacto blades
$1.45 I
XOK Exacto knife
$1.95 I
40411 RCA transistor
$2.50 1
TIP2955*- Flat pack
$1.00 I
TIP3055 Flat pack '
$1.00 1
FND500 .5" readout (cathode)
$1.95 1
FND507 .5” readout (anode)
$1.95 1
EM403 300V 1A diodes
6c 1
22K Double gang linear pots
69c 1
47K Oouble gang linear pots
69c 1
100K Double gang linear pots
69c I
47K Double gang log pots
69c I
LM309K T03, 5 volt regulator
$1.25j
.only while present stocks last
74121 50c
74151 $1.00
74 ID (linear) 40c
SC141D $1.20
2500uF 25V 49c
8.2V zener 14c
12V zener 1^
24V zener 1^
27V zener 1^
30V zener 1/
BC350 pnp $
4016 CMOS 6C
7400
28c
7413
28c
7440
28c
7442
60c
7445
80c
7446
80c
7448
80c
7460
35c
7479
40c
7483 '
95c
7492
70c
7496
95c
I capacitors
■ Greencap... 100 volt
■ .001, .0012, .0015, .001$, .
.0022,
9c m
1 .0027, .0033, .0039, .0047,
.0056
’ 9c K
■ .0068, .0082, .01, .012, .015,
lie 1
■ .018, .022, .027, .033, .039, .047 11c 1
■ .056, .068, .082, .1, .12, .
15,
16c p
;| .18, .22
16c B
1 Greencap... 250 volt
■ • 2-7 , .33, .39, .47, .56,
36C H
1 .68, .82, 1.0,
55c 1
1 1.2, 1.5, 1.8, 2.2,
% 1
$1.00 I
1 Greencap*. . . 630 volt
■ .001, .0015, .0022, .0033, .
0039,
13c G
1 .0047, .0056, .0068, .0082,
.01,
17c G
I .015, .022, .033, .047, .1,
22c 1
1 Ceramics... 630 volt
■ 10, 12, 15, 18, 22, 27, 33,
39,
7C G
■ 47, 56, 68, 82, 100, 120, 150,
7 C G
1 180, 220, 270, 330, 390, 470
7c G
1 560, 680, 820, .001, .0012,
.0015:
, 7 C E
I .0018, .0022, .0027, .0033,
.0039,
, 7 c p
1 .0047, .0056, .0068; .0082,
7C B
1 Electrolytics. . . PC board
25V
50V B
■ 2.2, 3.3, 4.7,
lie
nc B
I 10, 22, 33,
13C
15C B
I 47, 100,
18c
22c B
I 220, 330, 470,
45c
57c G
I 1000 uF
55c
95c B
1 Electrolytics... Pigtail
25 V
50V B
1 2.2, 3.3, 4.7,
lie
nc B
1 10, 22, 33,
13C
15c G
I 47, 100,
18c
22c G
I 220, 330, 470,
45c
57c G
I 1000 uF
55c
95c B
I Tag Tantalums . B
I .1, .22, .33, .47, .68, 1.0,
35V
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1 2.2, 3.3, 4.7, 6.8, 10,
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showroom
| ELECTRONIC SUPPLY SERVICE SHOP f
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PO BOX 787, POTTS POINT, '
SYDNEY, NSW, 2011.
1 28 ELECTRONICS Australia, December, 1 976
♦
Greenwich Mean Time is the term now used almost universally by short¬
wave stations. However, the term Co-ordinated Universal Time has now
been adopted by scientists and astronomers, and some readers have
suggested that this should also become the preferred term for inter-
national broadcasters.
A recent correspondent, Howard Barnes, of
Auckland, New Zealand draws our attention to the
use of Co-ordinated Universal Time in the scientific
field and suggests it could be used in place of GMT.
However, the fact that no directive from the ITU has
been given to switch to the new time reference
means that there is little hope of adopting the new
symbol in the near future. As well, a change would
cause confusion with short-wave listeners,
Mr Barnes points out that the Royal Greenwich
Observatory (RGO) or as it was then, the Royal
Observatory Greenwich, in 1675 adopted the local
mean time, measured from noon on a 24 hour scale,
as GMT. This worked fine until Britain adopted this
meridian as its civil standard meridian in the 1800's
— and then the world adopted it in 1884. For the
present, it will be our policy to refer to time in Green¬
wich Mean Time as the magazine is read extensively
not only in Australia but in many other countries. By
using GMT it is simple for readers in any part of the
world to convert GMT to their own time.
ENGLISH FROM STOCKHOLM
A new service in English for reception in Australia
and New Zealand has recently been introduced by
Radio Sweden with a transmission from 1100-1130
GMT. Two frequencies are used, 9630 and 15305kHz,
and the service is daily except for certain Mondays
when the transmitters are off the air for maintenance.
The transmission, also beamed to Europe, could be
received on both frequencies.
The test transmission in Swedish for this area con¬
tinues on 9605kHz 0630-0800GMT for the period up
to March 7 1977. Single sideband tests also continue:
0500-0800GMT 17775kHz; 0900-1300 17770;
1300-1400 17835; 1400-1600 17775; 1600-1800 15390;
and 1800-2130 11770kHz. The transmitter is located
at Horby, and the power is 30kW. A special verifica¬
tion card has been issued for these single sideband
transmissions of the programs of Radio Sweden,
Stockholm.
BROADCASTS FROM TIMOR
Now that some stability has returned to Timor, the
radio scene is much clearer and broadcasts from both
Kupang and Dili have been heard.. Radio Republic
Indonesia, Kupang, is broadcasting on 3550kHz up
to 1520GMT. At 1400GMt a news bulletin in
Indonesian was presented from the Kupang studios
with several local identification announcements.
Several Melbourne listeners report reception on
3550kHz and have also observed a relay on
3385kHz. , . . ,
Radio Dili, which has been recently proclaimed the
49th RRI station of the Indonesian network, has been
heard on 3120kHz at 1330GMT with a Portguese
Notes from readers should be sent to Arthur
Cushen, 212 Earn Street, Invercargill, NZ. All
times are GMT, add 9 hours for West Aust.
Summertime, 1 1 hours for East Aust. Summer
time and 1 3 hours for NZ Summer time.
identification. The station closed at 1400GMT and
used Via Condios as its closing melody. John Camp¬
bell reporting in "Down Under" DX news states that
the station has also been heard on 3395kHz and a
verification has been received. It came in the form
of a postcard following a report to Dili.
VENEZUELAN SIGNALS
A new ail night Venezuelan is Radio San Sebastian
on 6070kHz, first reported by Jack Buckley of Sydney.
Signals are only weak, and the station gives its slogan
and frequencies about every 30 minutes. Further¬
more, 6070kHz is blocked around 0750GMT by a
strong Indonesian signal, so that reception is con¬
fined to about one hour of listening.
Another signal from Venezuela, that of Radio
Nacional, is reported in DX post by Bill Vogel of
Adelaide. The station broadcasts from Caracas on
15390kHz and was heard from 0140 to 0230GMT.
Other reports indicate that the station has a broad¬
cast in English 2200-2300GMT and that it is using
15490kHz, though it announces as using 6170 and
15390kHz.
VEITNAM RADIO
Ho Chi Minh City Radio stated that Liberation
Radio had fulfilled its mission and had been closed
down, according to the BBC Monitoring Service.
With a view to better serving its listeners, the Voice
of Vietnam is setting up a separate program network
originating from the Central Radio broadcasting sta¬
tion in Ho Chi Minh City. The address of the station
headquarters is No. 7 Xo Viet Nghe Link Street, Ho
Chi Minh City.
Transmission time is from 2200-1605GMT and this
period includes a considerable number of relays from
the Voice of Vietnam, Hanoi, consisting of news, cur¬
rent affairs, people's Army broadcasts and
ideological talks! Frequencies for this service are
announced as 870, 6165 and 9620kHz. A continuous
relay of the Voice of Vietnam, Hanoi, is given on
720kHz.
CANADA RETIMES SERVICE
After broadcasting to the South Pacific for nearly
30 years for our evening reception. Radio Canada in
Montreal has made a major schedule change. The
service to the South Pacific is now scheduledYor our
morning reception. The new transmission time is
2000-2030GMT in English and 2030-2100GMT in
French. Three frequencies are being used: 15290,
15325 and 17820kHz.
In the past the transmission had been scheduled
0800-0900GMT and was a continuation of broadcast¬
ing after the service to Africa closed at 0800GMT. For
a time, the broadcasts were 1 000-1 100GMT, which
meant that the transmission was before the normal
service to North America.
BROADCASTS OF BHUTAN
Broadcasts from the tiny state of Bhutan are now
on a regular basis according to Adrian Peterson of
Poona, India. He reported reception of a special test
transmission on 7040kHz, commencing at 1230GMT
and using the station's 300W transmitter at Thimpu,
{the Bhutanese capital).
This is now a regular weekly transmission
1230-1 330GMT and during the first progam consisted
of English talks about the National Youth Association
of Bhutan and about Bhutan in general. Selections
of both European and Bhutanese music were also
played during the one hour broadcast.
RADIO INCA LIMA
A newcomer to short-wave broadcasting is Radio
Inca Lima in Peru, which is operating on 4762kHz and
closes around 0600GMT. This station relays OBX4E
on 1470kHz which has been operating in Lima for
some years.
The shortwave outlet was first noticed in New
Zealand by Dene Lynneberg of Wellington, and later
reported by many other readers of the New Zealand
DX Times. The station is announcing the short-wave
frequency as 4762kHz, but has been measured on
4763kHz. The station has typical Spanish programs
and has the address of The Director, Radio Inca del
Peru, Avenue Nicolas de Pierola 533, Lima, Peru.
MEDIUM WAVE NEWS
AUSTRALIA: Charters Towers is to have a radio ser¬
vice with a repeater to be installed in the area to relay
the program of 4AY Ayr Queensland. The power will
be 100W, but the frequency has not been allocated.
Programs will be fed from 4AY which at present
operates 24 hours a day on 940kHz.
The West Australian Institute of Technology is now
operating on 930kHz with 500W and has the call-sign
6NR. This is the second projected medium-wave sta¬
tion to be operated by a University, according Ian
Stanley reporting in "Tune In".
Radio 5SE at Mount Gambier is now operating 24
hours a day on 1300kHz. According to Mark Shiell,
Renown Park, SA, the station has moved into new
studios at Commercial Street West, Mt. Gambier.
INDONESIA: The increasing number of medium-
wave stations being put into operation in Indonesia
has resulted in the country being well received on
this band. Chris Martin of Sydney reports the recep¬
tion of Jakarta on 999kHz at 1500GMT. Transmitter
power is 300kW. Another new station opened
recently and uses lOOkW on 820kHz, and is located
in Medan.
CANTON ISLAND: According to a letter received by
Philip Brooks, Wanganui, NZ, station WXLE is to con¬
tinue operation on a voluntary basis. Station WXLE
was scheduled to close when forces pulled out of the
' island, but continued to operate 24 hours a day using
tapes and live shows on 1385kHz. The staff find
enjoyment in providing a radio service for the local
population, and for ships and aircraft in the area.
AFRICA
GABON: According to Peter Bunn of Melbourne,
reporting to "Australian DXers Calling", a verification
from Radiodiffusion Television Gabonaise states that
the Franceville facility operates on 3350kHz and
4830kHz using 4kW and 20kW respectively. Both
channels are scheduled 0430-0630 and
1700-2200GMT.
GHANA: Radio Ghana was heard on 6130kHz at
2125GMT by Bill Vogel, reporting in "DX Post". The
signal was heard to 2200GMT when interference was
experienced from Deutsche Welle.
ASIA
NORTH KOREA: Radio Pyongyang has supplied their
English schedule which gives their broadcasts as
follows: 0600-0800GMT 9820 and 12075kHz,
1000-1100 7203 and 9768; 1200-1400 7580 and 9769;
2300-2400 11535 and 15630kHz.
NORTH YEMEN: Radio San'a has changed frequency
from 7235 to 7265kHz according to the BBC Monitor¬
ing Service. The transmission schedule is 0300-0700
(1000 on Fridays), and 1100-2200GMT.
BRUNEI: Radio Brunei broadcasts in Malay on
4965kHz 2200-0600, 1100-1215, 1230-1430, and on
Fridays and Sundays 2200-1430. English transmissions
are from 2258-0030, 0300-0500 and 1200-1430 on
7215kHz, according to Bill Vogel of Adelaide.
PAKISTAN: Radio Pakistan has been heard on 15110
and 17665kHz at 1100GMT with slow speed news in-
English for Western Europe. The transmissions lasts
for 15 minutes. ^
ELECTRONICS Australia, December, 1976 129
MUSICOLOUR III
* For the disco, light show, party,
nites, or just relaxing . . enjoy
your records and tapes more
with the new magical
Musicolour Organ. Simple to
connect to the home stereo or
P A. system. 3 channels, 1500
watts max. load each
Fully constructed, ready to operate $69. 95
Complete kit of top quality parts and instructions— $59.95
P.P. NSW $3.50, interstate $5.50.
30 WATTS OF EXCELLENT HI-FI
WITH PLAYMASTER LOUDSPEAKER SYSTEMS
3-45L. Features the mighty 8-30 woofer 6J midrange and the
incomparable Philips AD016/T8 tweeter this top quality low
cost 3 way hi fi system is available from stock in either walnut
or teak veneer and complies with the specs , as per April 75
$84.00 each
3-41 L. As described in June '76 E.A. Again features the mighty
8-30 woofer, with the advantage of the new Magnavox 6-25
midrange, and the more elaborate cross-over network. The dome
tweeter is Philips AD0 1 60/T8 Beautiful teak, or the ever popular
walnut veneer cabinets are available. Either system can be
carefully packed and despatched per airfreight passenger rail or .
road. Packed weight approx. 40kl pair. $96. 00 GdCll
FAMOUS MAGNAVOX AUST. MADE LOUDSPEAKERS
MODEL.
Imp
Watts.
Rms Reson.
Hz Freq. Hz
V.C.Dia.
Price
P.P
10-40 10"
8
40
45
30-8000
1 Vi"
$20.95
$2.50
8-30 8"
8
30
45
30-8000
1 Vi"
17.50
2.25
1 2WR 12"
8
16
45
30-16000
1'
14 95
2.00
1 0WR 10"
8
16
45
30-16000
1"
12.65
2 00
8WR 8"
8
16
45
30-16000
1"
10.75
2 00
6WR 6 Vi
8
12
45
30-16000
1"
9.90
22.00
6.J 6 Vi
15
8
85
80-7000
1"
7.50
1.50
6-25 6 Vi
8
25
45
45-6000
1 Vi"
14.95
2.00
XJ3 Dome
8/15
25
1500
2000-20000 1
7.80
1 30
SPEAKER KIT SYSTEMS
E.A. 3-45L CONSISTS OF 8-30 WOOFER. 6J MIDRANGE, PHILIPS AD01 60/ + 8
TWEETER. AND CROSSOVER COMPONENTS $41.75. -I- P.P E.A. 3-41 L. CONSISTS OF
8-30, 6-25 MID AD01 60/T8, AND CROSSOVER COMPONENTS $49.95. + P.P
MAGNAVOX MV 50. 10-40 WOOFER, 6-25, TWO x J3 1" DOME TWEETERS AND
CONSTRUCTED FREQUENCY DIVIDING NETWORK. $71.00 +P.P. ALL KITS INCLUDE
INSTRUCTIONS
EXPO AM/FM clock radio
With alarm Wake up to either music
or buzzer 240VAC 50Hz
$33.95 P&P $1 50
SANYO CADNICA RECHARGEABLE
Sealed nickel cadmium batteries Type A. $1 99 EA 4 for $7.40 Type C $3.40
Type D $4 00 EA 4 for $12 40 2 for $7 50 P.P. $1.00 I' STATE $1.75
SANYO NI-CAD BATTERY CHARGER $22.00 P.P. $ 1 60
C-B 27MHZ COMMUNICATION EQUIPMENT
GEAR TO SUIT BUSHWALKER, FISHERMAN
TRUCK, BOAT OWNER
CAR.
Model NC-310. Features 3 channels. Battery checker, squelch
control, tone call switch, external aerial, speaker and power jacks,
battery charger jack, spec 1 3 transistors. RF input power. 1 watt
TXfreq Tol ± 0.005%. Tone call freq. 2000 HZ. RX. Sen0.7UV
at 10dB SN. sel 45dB at ± 10KHZ. If freq 455 KWZ
$49.95 complete with book and circuit, p.p. $1.60 interstate
$2.95
Model 2 Mobile 6 channel 5 watts. 14 transistors, 8 diodes,
squelch control, sig. strength /RF meter, microphone, book and
circuit. 12 volt operation. Size 4%" WX 1 Vi" HX 6-%" d
$99.00 p p. $2.50 interstate $3.50.
WESTON 5 WATT C-B TRANSCEIVER
Great boat or mobile rig Auto noise limiter, squelch. A G.C. over-
mod limiter Low pass filter for bandwidth SPECS T-mitter Crystal
locked. 5 watts input to RF stage Freq coverage Any 1 1 channels
in 27 MHz band Receiver, crystal locked double superhet 6 5
MC and 455 Kc Ifs 3" speaker dynamic mic 50 ohm antenna
20 1 sistors. 8 diodes. 1 2VDC operation. Sensitivity 0 5UV 10dB
S/N Size 616" x 2yz" * 7%" Wt 4'6 lbs
PRICE $ 1 35.50 p.p N S W $4 50. Interstate $5 50
27 MHz. C-B ANTENNAS
BASE STATION RINGO $49.00 P P. $3.50. STAINLESS STEEL CENTRE LOADED WHIP—
?^«STR0NG MAGNET BASE NO HOLE REQUIRED— INSTALL AND DISMANTLE IN
SECONDS 1 1 FT 52 OHM CABLE INCLUDED. $23.95. 520HM 74 CM S/S CENTRE
LOADED, COMPLETE WITH SINGLE HOLE MOUNTING BASE, ACCEPTS PL 259
MTRS. WI?H LsE .17.MP.PR*G21M.S ^ & M°B'LE HEUCAL ' 55
$57.00.
GARRARD MODEL 82
A superb 3 speed transcription changer / player
Auto manual operation 4 pole magnetically shielded
syn motor Resiliency mounted Counterbalanced
Elegant tone arm with slide-m cartridge carrier cali¬
brated Antiskate 265mm (lO’/z") Aluminium platter
Cue and pause control Cartridge tilting lever Magnetic
cartridge diamond stylus Size 375 x 335 x 170mm
( 1 4%" x l3'/4" x 6V4") 4 5kg (10 lbs) P‘& P $2 50
Interstate $3 50
GARRARD CHANGER /PLAYER
MODEL— 6400 3 speed auto manual changer— player
2 spindles. Motor 2 pole 240V 50Hz lOVi" turntable
cue and pause, tubular section pick up arm, Sonatone
cartridge. Great value 28.50.
Christmas special free — no charge
©"WOO00'0 6 tranS'St0r portable radio <as reviewed by E.A.) with every order in excess
HI FI CABINET KITS
Do it yourself —big savings Our kits are extra
easy to finish Top. bottom, each side and
back are factory assembled baffle is pre-cut
Veneered pyneboard Teak or walnut
Complete with mnerbond and speaker grille
cloth 8-30 3-45L. 3-41 L systems $48.00
pair
MV-50 system $65.00 pair
FRG-7
YAESU MUSEN RECEIVER
$252.00
PHILIPS AD0160/T8
1" DOME TWEETERS
$22.00 PAIR P.P. $2.50
9 BAND PORTABLE RADIO
BATTERY— 240VAC
$52.95
Features. Push/B band selector, slide vol. ton. Squelch
controls, time zone dial, world map, 2 telescopic anten¬
nas. twin speakers, tuners, broadcast, ham. SW. marine
aircraft, police. FM weather baqds.
P P. $150. INTERSTATE $3.00
PACK OF 20 NEW
POTENTIOMETERS.
5K TO 2MEG
SINGLE AND TANDEM
$1.50 P.P. 75c
GARRARD 3 SPEED
RECORD PLAYER. 240V 50HZ
MODEL SRP-22. COMPLETE WITH STEREO
CERAMIC CARTRIDGE BASE/PLATE
SIZE 1 1" x 8'/2''
$10.75 P.P. $2.50/l'State $3.00
HORN TWEETER
PLESSEY MODEL X20
3000-30000 Hz. 20 WATT
ONLY $6.50 PP 95c
RED ROTATING
DISTRESS BEACON
For car. truck or boat, fits with heavy duty sue
tion cap. 12 volt 2 amp. $9.95. P-P NSW
$1.50 Interstate $2.50
TRANSISTORS AND DIODES
ALL NEW GUARANTEED MANUFACTURERS' STOCK
2N 3055 12 FOR $7.20 IN 4723R 600piv 3AMP 12
FOR $3.60 BONUS BUY $ 1 5 00 WORTH AND GET
A USEFUL PACK OF TRANSISTORS DIODES.
ZENERS. AND LED BUY $25 00 WORTH AND YOU
GET THE TRANSISTOR PACK PLUS FOUR 2N 3055
MINI RELAY
12 VOLT 500 OHMS DPDT IN PLASTIC CASE FOR
PC BOARD MOUNTING %" x x 7/e"H
$1.95 P.P. 45c
LM 377 N.
2 WATTS AUDIO DIL 1-C
2 for $1.95 P P 55c
REFLEX HORN SPEAKERS
EXCELLENT REPRODUCTION IDEAL FOR PATIO OR
POOL BACKGROUND MUSIC, OR PA APPLICATION
80HMS 6"DIA 10 WATT $15.00 8"DIA. 10 WATT
$17.00 8" x 5" 15 WATT $18.50
p.p. $1.50 INTERSTATE $2.50 •
50 WATTS RMS GUITAR/P-A AMPLIFIER
4 INPUTS. 2 HIGH. 2 LOW. 2 CHANNEL EACH CHAN¬
NEL HAS SEPARATE VOLUME, 8ASS AND TREBLE
CONTROLS BOTTOM CH HAS VIBRATO WITH
SPEED AND INTENSITY CONTROLS. SENSU
TIVITY - 25 AND 200 MILLIVOLTS FOR 50 WATTS
OUTPUT AT 500HZ AT 8/ 1 6 OHMS REMOTE FOOTS-
WITCH WITH PLUG AND LEAD INCLUDED. ALSO CIR¬
CUIT. 240 VAC50HZ $ 1 39.50
12" 60WATT RMS E-TONE SPEAKERS $45.00
HI-LO IMP ELECTRET MICROPHONES $26.00
WE REGRET THAT PRICES ARE SUBJECT
TO CHANGE WITHOUT NOTICE
130
ELECTRONICS Australia, December, 1976
INFORMATION CENTRE
CHRISTMAS TREE LIGHTS: With the
approach of the festive season I wonder
if you will give some thought to the
problem of Christmas tree lights. The
annual ritual of getting the conventional
series wired systems into working order
is expensive and time consuming. Lamps
invariably fail and, last year, the problems
were compounded by the complete
unavailability of spare lamps.
I have thought of using low voltage
LEDS powered by a transformer rectifier
combination. I also envisage two, or
more, strings of lamps of different
colours operated from some form of
sequential flasher. (M. K., Waramanga,
NSW.)
• Many thanks for the suggestions, M. K.,
and we will certainly keep these in mind.
Unfortunately there are problems, not at
least of which is to provide a suitable
transformer, with adequate insulation
ratings, at a reasonable price. And, once
such a transformer is provided, it may
well be worthwhile retaining the original
style lamps with their higher output. One
suggestion was to drive three different
coloured strings of lamps from a
Musicolour, operating from appropriate
musical numbers. While an intriguing
idea, it would be easier to do with series
strings at 240V than with low voltage
parallel strings. Right now we are not sure
how popular your idea would be with
readers, particularly considering the low
cost of typical lamp sets.
DX LISTENING: I read with interest your
article on the LF and VLF Converter,
described in March, 1976. 1 am interested
in DX listening (and viewing) on TV, MW
and LF bands and at one time I had a
Marconi receiver from a submarine, and
which tuned down to 10kHz. Many
interesting signals were heard, even at
these very low frequencies. However,
the most interesting listening was on the
LF broadcast band of 150kHz to 290kHz.
I have received QSL cards from at least
nine stations located in various parts of
the USSR, using an aerial one hundred
metres long. Reference to the World
Radio & TV Handbook shows that there
are now nine stations radiating from
500kW to 800k W and thirteen more on
lOOOkW to 2000k W on this band. I hope
to obtain a new receiver with loop aerial
and preamplifier in the near future and
continue my DX activities on these
bands. Also, over a six week period, I was
able to log seventeen TV stations from
three countries. The distances involved
were from 1500kM to 4500kM. (B. C.,
Windsor, Qld.)
• Thank you for your letter and the
interesting experiences you have had on
the low frequencies and the TV bands.
We agree that there are a lot of signals
to be heard, particularly in the low
frequency broadcast band, and it would
seem that very few people have explored
these regions. Although time is a limiting
factor, we are also interested and we
hope to do more along these lines in the
future.
PROJECTOR: I have the opportunity to
buy a Siemens 2000 projector. I wonder
if any of your readers might be able to
supply me with information on this
projector. (P. Fuller, 24 Perman St, New
Lambton, NSW, 2305.)
• We have printed your full name and
address, Mr Fuller, so anyone who can
help will be able to write directly to
you.
DESPATCH
SERVICE
869 GEORGE STREET
SYDNEY
CNR GEORGE & HARRIS STS
RAILWAY SQUARE
TEL 211-0816. 211-0191
OPEN MON. TO FRI.
8.15AM TO 5.30 PM
SAT. 8.00 AM TO 1 1 .45 AM
Our Comprehensive Stocks
include: —
T V. AERIALS & ACCESSORIES
TRANSFORMERS
SPEAKERS
I.C. & SEMICONDUCTORS
POMONA SHIELDING BOXES
SOLDERING IRONS
ELECTRONIC HANDBOOKS
CASSETTE TAPES
REPLACEMENT VALUES FOR
NATIONAL T V.
P C. BOARDS
OPEN SATURDAY MORNINGS
BARGAINS!!
Super bargain packs month at Micronics.
Just try a few. Be surprised at the value
you are getting. If you are not satisfied
we'll refund your money. These are a
must for the hobbyist and serviceman.
Order these now, while still available.
Styroseal pack caps— New, Top Quality-
20 for $ 1 . Power resistor pack (Up to 7w
Power Resistors)— 20 for $2.50. Poten¬
tiometer pack incl. Dual gang, Single gang
and trimpots (no junk)— 10 for $2.75.
Semiconductor pack: Fantastic Pack of
silicon germanium transistors and other
semiconductors— 20 for $2. Rotary switch
pack: Fantastic value in . Rotary switches;
you will be amazed!— 3 for $3.50. Elec¬
trolytic pack: Incl. High and Low voltage
electros— 25 for $2. Resistor pack: 100
per pack (incl. 5%, 1 0%, Viw and 1 w types)
—2 packs for $ 1 80. Polyester cap. pack:
100 per pack. New range of values from
1 60 to 400v (fresh stock)— 1 00 for $ 2 .7 5
Tag strip pack. Miniature Current types —
25 for $2 Miscellaneous bargains: Poly¬
ester Greencaps: 0.001 uf/ 1 0Ov— 20 for
$ 1 . 01 uf / 1 OOv— 20 for $ 1 .20, 1 uf / 200v
—3 for $1 . Valve sockets (7 pin)— 20 for
$ 1 . Feed through ceramics: 1000pf(350v)
— 1 0 for $ 1 . For free offer and more super
bargains see other Advertisements in this
issue Post and Pack 60c, extra for larger
parcels. _
MICRONICS
P.0. Box 175, Randwick. 2031
If you are unable to complete an Elec¬
tronics Australia" project because you mis¬
sed out on your regular issue, we can
usually provide emergency assistance on
the following basis:
PHOTOSTAT COPIES: $2 per project, or $2
per part where a project spreads over mul¬
tiple issues. Requests can be handled more
speedily if projects are positively identified,
and if not accompanied by technical
queries.
METALWORK DYELINES: Available for
most projects at $2 each, showing dimen¬
sions, holes, cutouts, etc., but no wiring
details.
PRINTED BOARD PATTERNS. Dyeline
transparencies, actual size but of limited
contrast: $2. Specify positive or negative.
We do not sell PC boards.
REPLIES BY POST: Limited to advice con¬
cerning projects published within the past
2 years. Charge $2 We cannot provide
lengthy answers, undertake special
research or discuss design changes.
BACK NUMBERS. Only as available. Within
last 6 months, face value. 7-1 2 months, add
5c surcharge; 1 3 months or older, add 1 0c
surcharge. Post and packing for 60c per
issue extra.
OTHER QUERIES: Technical queries out¬
side the scope of "Replies by Post" may be
submitted without fee, for reply in the
magazine, at the discretion of the Editor.
COMMERCIAL SURPLUS EQUIPMENT:
No information can be supplied.
COMPONENTS: We do not deal in elec¬
tronic components. Prices, specifications,
etc., should be sought from advertisers .or
agents.
REMITTANCES: Must be negotiable in
Australia and made payable to ' Electronics
Australia".
ADDRESS: All requests to the Assistant Edi¬
tor, ‘Electronics Australia ", Box 163,
Beaconsfield, 2014.
ELECTRONICS Australia, December, 1976
131
BC221
FREQUENCY METERS
Brand new in original packing cases—
unopened complete with 240 volt power
supply Charts etc $90 each— cartage to
rail $2. Freight payable at nearest attended
Railway Station
P.M.G. TYPE TELEPHONES
Standard desk type with magneto bell
calling device Range 30 miles Uses
standard batteries at each phone Any
number can be connected together on
single line.
$35.00
<2 TELEPHONE SETS)
$ 2 Cartage to Rail Freight payable at nearest
attended Railway Station.
TEN CHANNELS
VHF TRANSCEIVER
TR 1 956 125-150 MHz 28 volt DC oper
ated AM single crystal locks both TX and RX
on same channel complete with generator
$33.00
TUNING UNITS
T U Series Contains variable condenser
suitable for aerial tuning, vernier 5" Ceramic
Coil Former, etc 1 9" rack mounting, only
$9.50 ea. Post A $2 30. B $375
C $4 80. D $6 55
FREQUENCY METERS
A* 1? A ,?0 KH* 1000 MHz.
with 240V power supply. $125
$ 2 Cartage to Rail Freight payable at nearest
attended Railway Station
ILFORD 17 5 mm
SPROCKETED
MAGNETIC TAPE
1000 ft reels brand new original packing
$4.00 ea. quantity
available
Post A $1 30 8 $2 00
_ C $2 30 D $2 80
No 62 TRANSCEIVER
With headphones accessories etc
$60
TELEPHONE WIRE
1 mile twin(2 miles) genuine ex Armt
Don 8 perfect condition $35 per drum
$1 cartage to rail freight payable at
destination
PRISMATIC COMPASSES
Genuine ex army Mk 3 liquid damped a?
new $45 00 P 8. P A $ 1 70 B $2 25
_ C $2 40 D $ 2 65
morse key I morse key buzzers
5140 $4.25
Post 40c I Post 60c
DYNAMIC
TRANSISTOR CHECKER
Provides a visual indication of signal output
Tests electrode open circuits short circuits
current gam $14 95ea
P & P A$1 70 B$2 25 C$2 40 D$2 65
MULTIMETER
A compact and handy tester for
workshop or lab where quick circuit
checks are required
DC Volts 2. 5 to 1 ,000V (20.000 OHMS per
volt) AC Volts 10 to 1.000V (10.000 OHMS
per volt) DC Current 50 UA 25 MA 250 MA
Resistance 40 K OHM. 4 MEG OHM Deci¬
bels minus 20 DB plus 62 DB complete with
instructions only $17.25 Ea. PP $1 05
Multimeter similar to above 30.000 OHMS
per volt $23.75 P P $1.05
Only $ 1 7 25 ea Post $ 1 05
BENDIX PIONEER
Drift Sight
Type B3
$250 00
4 DIGIT RELAY COUNTERS
JOvolt OC. suit Slot cor Lop counters.
• 1 25 each P «, P 60c
NIBBLING TOOL
Cuts sheet metal like a punch and die,
trims, notches and cuts to any size or
shape over 7 16inch.
ONLY $9.95
Post $ 1 10
POSTAGE KEY
A: NSW
B: Vic, Qld
C: SA, NT, Tas, New Guinea,
D: WA
NIFE CELLS
1 2 Volt, fully charged, 4in x 3in x 1 in 4
AH
$1 50 each P & P 80c
5" CRO TUBE 5 BPI $5 50 each
Post A $1 40 B $2 25. C $2 70 0
$3 45
HANDY SIGNAL INJECTOR
Produces an Audio Signal in rich
harmonics Ideal for Sig Tracing in
A F , I F , and R F circuits Powered
by 4 Penlight Batteries with On Off
Switch and indicator lamp Size V ?"
□ •am 5” Long Only
$6 50 Post $1 10
522 Transceivers 100 ISOM CS
$35.00
VALVES
BRANDNEW INCARTONS
65N7GT
95c CV850
$1.50
5U4G
95c 1H6G
75c
6 F 50
75c 832
$5.00
5Y3
$2 25 6X4
$2 25
2x2
75c VR65
P & P 40c
75c
AIRCRAFT CLOCKS
Genuine eight day jewelled movement
sweep second hand Dash mounting
$29.50 EA. P & P $110
CONDENSER LENS
1 Vj" Diam 4 ’/j" F L 75c 2 VS" Diam 2" F L
$ 1 50 each Or $2 50 per pair p & p 40c
ZOOM SPOTTING
SCOPES
30x30
LENGTH 12y2", HEIGHT
10"
WEIGHT 1 % lb.
$23.95
45x40
LENGTH 16".
HEIGHT 10"
WEIGHT 2 lb.
$36.50
SPY TELESCOPES
8x17 may size of a rifle cartridge extends
to 8" Only $4 75 each post 60c
BINOCULARS
PRISMATIC Coated Lenses Brand
new Complete with case
7 x 35 Wide Angle «o
8 x 40 W.de Angle .so
' x 50 j!] in
1° x 50 Hi ll
21 * 5° $33.45
20 x 50 $37.95
P 8. P A $1 80 B $2 50 C $2 20
0 $3 20
SMALL CLIP ON
POCKET TELESCOPE
1 5X $3 95 Post 60c
RECEIVER No 210
2 16 M/cs *65
Transmitter No 1 1 suits 210 $35
24 volt Power supply to suit above $15
Or complete station with Headphones Mic
Morse Key Antenna $110
High grade coated lenses.
Ideal for pistol and rifle
ranges or general viewing.
Zooms in from very low to
high powers. Complete with
tripods.
POST: A. $1. 70, B $2.25.
C. $2.40, D. $2.65.
TELESCOPES
25 x 30 $6.50
P & P A $1.70. B $2.25 ✓
C $2 40 D $2 65
IMPELLER PUMPS
New gun metal body. Stainless Steel
Shaft Neoprene impeller Up to 15ft
Lift, suitable for almost any type of
liquid Self prining ideal boat bilge
pump, sullage drains, etc Approx size
8" x 5"
% $23.30
Vi $31.95
P & P A $1 90 B $2 75 C $3 20 D
$3 95
~56LEN0IC>5
Plunger Type 12V 300MA Suit electric
camera control, miniature trains,
radio etc
12.50 P & P 20c
200 MA 24 volt. Vain push movement
$2.50 P & P 20c
SELSYN MOTORS
MAGSLIP
3000 TYPE RELAYS
P M G 2000hms — I 'SOOOhm
Coils *2 50 each P 8, P 60c
LAVOIE FREQUENCY METER
Fr-/6U
100 to 500 M/HZ
240 Volt operated
PERFECT CONDITION
$375 00
SPECIAL lucky dip valveoffer, 15 new
valves in cartons for only $2.95 We
haven't got time tq sort them, so you
reap the benefit.
P 8i P A $1 80 B $2 50 C $2 80
SMALL COMPUTER
PANELS
3in x 2m containing 2 valves, qty of
resistors, etc
* ONLY 75c P 8i P 60c
ELECTRONIC FREQUENCY
COUNTER
Austronic type DFC 4 240V 50 cycle 0
$150
lOOKHz
PANORAMIC ADAPTOR
E M I type PRA 1 455 variable Kc
Course 440-520 Kc
Centre Freq 520-440 Kc
Fine Centre Freq 20-0 20
Filter band with 50. 100 200 L F
200 H F Sweep band width 0-200
TRANSCEIVERS
Ex Army
No C42 set 36 to 60 MHz complete with
24V power supply headphone, mic,
leads etc $65 00
No C45 set 23 to 38 MHz complete with
mast headphones mic. 24V power
supply etc $95 00
*1 00 cartage to rail freight payable at
nearest railway station
Hartley double beam oscilloscope Type
1 3A with probes
Working $150 00
77D x RCA STUDIO RIBBON MICRO¬
PHONES Variable pattern 8i response music
or speech $80 00 ea Post A $3 30
B $4 00 C $4 30 D $4 80
EX-ARMY TWO-WAY
FM RADIOS
1 2 WATTS OUTPUT
SUPERHET
PRC9 AND 9A 27 to 39 M/HZ
PRC10 AND 1 0A 38 to 55 M/HZ
WITH HANDSET
ANTENNA ONLY $25 EA
$ 2 Cartage to Rail . Freight payable at nearest
attended Railway Station.
1 6MM SOUND PROJECTORS
IN GOOD WORKING ORDER
240 volts operated Complete with Speaker
and Amplifier
CINEVOX $150.00
BELL 8< HOWELL $250 00
SIEMENS $375.00
$2 Cartage to Rail. Freight payable at nearest
attended Railway Station
WALKIE TALKIES
2 WAY RADIO,
PMG APPROVED
1 watt, n transistor $142 set of 2
P 8. P A $1 80 8 $2 50 C $2 80
0 $3 20
MICROPHONES
OMNI DIRECTIONAL
50K OHMS
FREQ RESPONSE lOO-IO.OOOHz
Sensitivity 56dB complete with 5ft cable
Microphone Holder and Stand Base only
$7.95 ea
P&P A$1 70. B$2 26. C$2 40. D$2 65
REPERFORATOR
Genuine Siemens Type 33c $65 00
P.M.G. TYPE KEY SWITCHES.
75c P & P 20c
Cossor Double Beam Oscilloscope 1035
Tested
Deitch Bros.
70 OXFORD STREET, SYDNEY 2010
SORRY NO C O 0
132
ELECTRONICS Australia, December, 1976
SC/MP Editor . . . from p 93
Note that following the input of an A,
R, or I command, the editor enters its
text-input mode of operation. It will nor¬
mally remain in this mode until it detects
a "bell" character, whereupon it returns
to the command mode, ringing the bell
to indicate its response. If a tape being
read in following the R command is ter¬
minated with a bell character (having
been punched previously using the B
command), this will take place auto¬
matically at the end of the tape.
All commands other than A, R or I
cause the editor to return to command
mode automatically when the command
function has been performed.
Note that the editor will also return to
the command mode automatically dur¬
ing text input (including during editing
which involves additional text), if either
of the internal line or text buffers become
full.
The number of text lines held in the
editor's buffer may be found at any time
by typing an oblique (/) while in com¬
mand mode. The editor will immediately
type the current line total, in decimal.
When accepting text from the key¬
board, the editor will detect a "percent"
character (%) and interpret this as a de¬
structive backspace. This may be used to
correct character errors if they are
noticed very shortly after entry (i.e.,
before the end of the line). Each percent
character is interpreted as a one-
character backspace, and the character
may be used repeatedly to backspace
BULK SALE!!
Discount for Quantity Sale. Ideal for Radio
Clubs, Servicemen and Group Buyers. Feast
your eyes upon these prices — Electrolytics: 2.2
uf/50v Single Ended, Top Quality-200 for
$5.95. (S.E.) is single ended type. (P) is pigtail
type. 100uf/ lOv (S.E.)— 100 for $7, 220uf/25v
(S.E.)— 50 for $7.50, 47uf/63v (S.E.)— 50 for
$6 33uf/16v (S.E.)— 100 for $7, 47uf/50v
(S.E.)— 1 00 for $1 1, 1000uf/25v (S.E.)-25 for
$9, 470uf/25v (S.E.) — 50 for $11.50,
47uf/350v (P)— 25 for $ 1 1 , 22uf/350v (P)-25
for $8.50, 1 Ouf / 350v (P)— 50 for $13.50,
2.2uf/350v (P)— 50 for $10, 1uf/350v (P)-50
for $7.50, 1 OOuf /63v (S.E.)— 100 for $20,
640uf/16v (P)— 50 for $13. 50. Just arrived
new switches. Fantastic sale of switches.
These are top quality switches. Many miniature
types at incredible prices. We bought a certain
quantity so remember, once they are sold out at
these prices, you've missed out. ST103A Toggle
switch SPST— 10 for $3.50, MSPB206R Push <
button DPDT— 10 for $5.50, MSP106D Push
button SPDT— 10 for $4.50, MST206N Minia¬
ture Toggle DPDT— 10 for $8, MSL203N-5
Rocker switch DPDT — 10 for $6, MSH203N
Rocker Toggle switch DPDT— 10 for $6,
MSP103C Push Button SP— 10 for $2.50,
MST406N Miniature Toggle-10 for $9, MR3-3
Miniature Rotary switch— 10 for $ 1 3 New Panel
Meters: SD830— 10 for $35. Styroseal
Capacitors — Devastating Prices:
1 0 0 p f / 1 2 5 v - 2 0 0 for $4.50,
680pf/630v — 1 00 for $3.25,
680pf / 1 OOOv — 200 for $10. Tuning
Condensers— 2 gang— 10 for $13. The above
bargains are limited quantity lines only. Only
speedy action will enable you to benefit from
these super values. Post your order today! Post
and Pack 60c, extra for larger parcels. _
MICRONICS
P.0. Box 175, Randwick. 2031
right back to the start of the current line,
if necessary.
Before punching a tape following the
P or B commands, the editor pauses to
allow the user to turn on the tape punch.
Typing any character on the keyboard
then causes it to punch a leader, the
desired output text (followed by a bell
character in the case of the B command),
and finally a trailer. It then pauses once
more, to allow the user to turn off the
tape punch. After doing so, the user must
then signal the editor to continue by
typing any character via the keyboard.
The editor will automatically query any
illegal commands, including commands
which are not expressed in the correct
form. It will also query you if the
arguments in a command are either
inappropriate to the command, or not
valid for the text currently held in the buf¬
fer. For example if you have only 30 lines
of text and you give it a command like
45 L, it will promptly reply with a query.
The editor has been fairly extensively
tested, and to the best of my knowledge
it is now free of bugs. However, if you
should find a bug, I would appreciate
being advised so that all users can be
informed. ®
Notes & Errata
ASCII-BAUDOT TRANSLATOR (Octo¬
ber 1976, File No. 2/CC/15): Philips
Industries Ltd has advised that the Signe-
tics 2536 UART is no longer available.
However they are able to supply the TMS
6011, which is an exact equivalent
device.
RHYTHM UNIT (October-November
1976, File No. 1 /EM/42, 43): We have
been advised by C & K Electronics (Aust.)
Pty Ltd that they are able to supply bexel-
mounting paddle switches for the mute,
reset and rhythm group select switches,
having gold contacts to provide
improved switching reliability and longer
life. Designated type 7201-J61B, the
switches are available with actuator pad¬
dles in a variety of colours if required.
(C & K Electronics, Office 2, 6 Mac-
Farlane St, Merrylands, NSW 2160.)
LANTHUR
ELECTRONICS
69 Buchanan Avenue. North Balwyn.
Vic. 3104 P.0 Box 162. Ph. 85 4061
ELECTRIC DRILL
Speed controller kits. Will control speed down
to stop of any ac/dc brush type motor. No loss
of torque. Consists of triac, resistor, diodes,
pot., knob, 3 pin base, plug 8t circuit.
5 amp. size. (1 200 watt) $8.95
10 amp. size. (2400 watt) $9.95
Prices include postage
LAMP DIMMER KITS
Will control incandescent lamps down to out.
Consists of triac, diac, capacitors, resistors,
pot., knob, ferrite rod, wire & circuit.
5 amp. size (1200 watt) $6 95
10 amp size (2400 watt) $7.95
Prices include postage
PLASTIC CABINET
Suitable for above speed controller & lamp dim¬
mer kits. $ 1 55
Post free if with above kits otherwise plus post¬
age 0.40
ETCHING KITS
For printed circuit board. All you need to make
your own printed circuits, including a piece of
board 6x4 inches, and instructions. $4.95
Prices includes postage
BATTERY CHARGER KIT
Will charge 1 2 volt wet batteries at 2 amps
Consists of transformer, bridge rectifier, ballast
resistor and circuit. $9.75
Plus postage . Vic . $1.10
Other $2 00
BATTERY SAVER KIT
Will supply dc voltages from 6 to 1 5. Consists
of transformer, bridge rectifier, filter capacitor
and circuit One amp size $8.50
Plus Postage Vic. $1.10
Other. $2 00
Two amp size $16.50
Plus postage Vic . $1.15
Other $2 50
SPEAKERS
Australian made M S.P Good quality 4 inch 1 5
ohm $3.95
Price includes postage.
FAST DESOLDERING
wi,h Sod er -Wick
Soder-Wick is a specially treated
copper braid which soaks up
molten solder like a sponge.
Desolders a P.C. pad in a second
or so: acts as a heat sink to
protect circuits and components.
0v*-w/c
sW
Hold Soder-Wick on
termination with hot
soldering tip. Wicking
action soaks up solder
2.
Remove tip and braid.
Termination is left
clean and free of
solder.
In a range of sizes from
your wholesaler or
ROYSTON
ELECTRONICS
02-709 5293
03-848 3777
RE475
ELECTRONICS Australia, December, 1976
133
KITCRAFT WA
557 WELLINGTON ST
PERTH PH 21 3047
Kenwood 4 Channel Stereo
Amplifier—
With FM-AM Tuner and Belt Drive
Turntable with 2 Motors Plus 6 Speakers.
AT $299.00
Less Cabinets
TR 10CS-1 560
The 1 5MHz dual trace
Oscilloscope. Complete
with free x 1 0 probes.
Price $439.00
‘Plus S/Tax
WE ALSO STOCK.
• Books
• Amplifier Kits
• Turntables
• Speakers
• Speakers Kits
• Cabinets
• Security Equip.
• Electronic Kits
• Transceivers
• Calculators
• Test Equip.
• All Components
• Tapes
PERTH'S NEWEST
ELECTRONIC STORE
COME AND SEE
Marketplace
FOR SALE
RESISTORS AND CAPACITORS. Resistors all El 2 values.
’/4 watt carbon film. 10 ohm to 1 meg 2 cents each I.R.H
GL Vi or GLP. Vi watt Metal glaze 10 ohm — 470k 3 cents
each or 2.5 cents over 250. 1 watt 1 ohm to Ik 6 cents
each or 5 cents over 1 00 PACKS STANDARD PACK contains
5 each of El 2 values in ranges shown. COMPUTER PACK
contains quantities based on general usage. Vi watt 285
resistors $7.00. Vi watt 305 resistors $5.90. CAPACITORS
ELECTROLYTICS single ended uprights. Mfd 35 v.w. 1,2.2,
3.3,4 7, 10, 22, 10 cents each. 33.47, 15 cents. 25 v.w.
100 16 cents each. 220 25 cents each. 470 35 cents.
Polyester Greencaps 100 v.w. .001, .0022, .0033, .0047,
.0056, 0068, 7 cents each 01, .022, .033,. 047, .056,
.068, .082, 10 cents each. .1, .22, 13 cents each. Poly
Pack 5 cents of these values $6.00. 75 capacitors. Other
components see E.A. June, 1976. All components brand
new from manufacturers dr agents. Each value of component
individually packed. Post and packing included in all orders
over $6.50. For orders less than $6.50 add 40 cents for
post and packing. 5% discount on orders over $35.00. 10%
discount on orders over $75.00. Send orders to RAM ELEC¬
TRONICS, 575 Sydney Road, Seaforth, N.S.W. 2092.
Please send cheque or money order.
TELETYPES repaired. Spare parts. Paper Rolls, Machines for
Sale. NETWORK ENGINEERING Ph (02) 211 4630.
AUSTRALIAN RADIO DX CLUB The premier DX club of Aus¬
tralia now in its 12th year of national operation. Catering
for the interests of both S.W. listeners and DXers, the
monthly bulletin covers the S.W. and M.W. spectrums. For
full details enquire now to ARDXC. P.O Box 67, Highett,
Vic. 3190.,
AMPEX AG-440B STUDIO RECORDER, Full track mono,
lVi and 1 5 i.p.s. complete in walnut console on castors, with
built-in monitor amp. Excellent condition, has been used less
than 500 hours since new $2000. Vista electronics, 78
Robert Street, Wickham, N S W. Tel. Newcastle 61-4908.
10W. amp. with turntable & speakers, in teak cabinet $300.
Tape recorder — B.S.R. 3 speed 3 hd deck, pile of tapes,
all sizes, recorded & blank $200 Radios, player cases, bat¬
tery turntable — hundreds of junk box parts. Hobbyists can't
afford to miss this chance. G. Sankowsky (The Butterfly
Farm), Long Road. Mt. Tamborine. QJd. Ph. 075-451353.
Callers only.
FAST 14 DAYS P C. BOARD SERVICE for any project. 20
cents a sq.inch. Send in your magazine clipping of P.C.B
required (returned with your order) measure image area for
example:
6 in. X 3 in. «■ 18 in. X 20 cents ■■ $3.60, post 60 cents
P.E. JOANNA Touch Sensitive electronic piano May 75.
Complete set of 14 P.C.B's $30.90 P8tP $1 .20.
P.E. RADIO CONTROL June 76. Complete set of 8 P.C.B's
$12.50 P&P 80c.
P.W. RHYTHM GENERATOR June 76, A set of 3 P.C.B's
$11.50 P&P 60c.
NOVELTY MART, P.O. BOX 390
MASCOT, N S W 2020.
TELEPRINTERS Working to P.M.G. test tape. Creed 7B Tele¬
type 15. Readers 14 T.D. Reperforators 14 Info. Spares &
Paper & Tape. Distortion testers. Tone generators. Sent
anywhere freight forward plus packing. Studio 20 Sales,
31 3383. 367 Bourke St, Darlinghurst 2010.
COMPONENTS BARGAINS, Resistors 5% V4w 10 ohm 1
Mohm, Vaw 10 ohm to 10 Mohm 3c ea CAPACITORS
GREENCAPS. lOOv .001 to .0022 10c. .033, .047 11c.
.1 13c. .22 17c. 630V .001, .0022, .0047 13c. .01 15c
'022 16c. .033 18c. .047 21c. .1 23c ELECTROLYTICS.
pcb mounting 25V 5, 10, 25ufd 12c. 47 16c. 100 18c.
220 24c. 470 30c. 1000 50c. or 10 for $4.00. PRINTED
CIRCUIT BOARD 12" x 3" 40c. 6 for $2 12" x 4" 60c.
or 4 for $2. A&R PCI INSTRUMENT CASES $3.50. Min.
order $5.00 P & P 80c. add extra for heavier items.
G.H. COMPONENTS, PO BOX 378, GLEN WAVERLEY, VIC.
3150.
WIRE STRIPPER Labour saving hand held no damage to
cable. SELF ADJUSTING strips single multiples round or flat
conductors, up to size 7/029— one movement.
$ 19.95 -f 60c post.
TELECOM ADVICE. P.O. Box 105, Marrickville 2204, NSW.
BOOMERANG TAPE RECORDING CLUB - Full details 9"
x 4" S.A.E. P.O Box 118. Wellington, N S W. 2820.
WANTED
ELECTRONICS and similar magazines in good condition
bought, phone Healy (02) 631-6681 after 5pm.
"DUX CINE" Circa 1950 toy movie projector also 16" radio
serial discs. Box 36, Fairy Meadow, 2519.
TIME CLOCKS
HUGE SAVINGS!
SANGAMO
741 mDip Op Amp 4 for $ 1
LESS
723 Dil 2-37v Reg 55c ea
S ***■ DAY OMIT
CA2-30 mDip Opto Isolator $2 ea
/** e\ device
PA60 8A 600 PIV Bridge
[if: \ $13.50
Rect $3.50 ea
’i WITH
2200 uf 40V Electrolytics 80c ea
'**1 DAY OMIT
9"x416"x 1/16" F glass Laminate
Hlv / device
60c ea
/ $i6.oo
Pack & Post 50c
240 V 50 cs
1 5A Contacts
For more low cost quality components
Used tested and guaranteed
send SAE for free catalogue and start
PACK & POST N S W. $2.00
comparing our prices
Vic. & Qld. $2.50. W.A. $3.00
CLOCK DISPOSAL CO.
Linear Electronics
P.O. Box 147
PO Box 254
LINDFIELD, N.S.W. 2070
Punchbowl 2196
134
ELECTRONICS Australia, December, 1976
DISPLAY ADVERTISEMENTS IN
MARKETPLACE are available in
sizes from a minimum of 6cm x 1
col rated at $10 per col cm.
Other sizes are at card rates.
CLASSIFIED RATES $1.75 per line
per insertion payable in advance.
Minimum two lines.
CLOSING DATE is six weeks prior to
the on-sale date. Issues are on sale
the first Monday of each month.
ADDRESS all classified orders,
copy, enquiries, etc. to: The Adver¬
tising Manager, ELECTRONICS
Australia, Box 162, Beaconsfield,
2014.
ELECTRONICS AUSTRALIA
1976/77 YEAR BOOK.
Crammed with fascinating reading,
do-it-yourself projects, hand picked
record and book reviews, a full listing
of Australian and New Zealand radio
and TV stations, equipment reviews
and a look at CB in Australia . . $ 1 .20
FROM YOUR NEWSAGENT
FREE OFFER!!!
Free offer of 5 of BC548 (New. Branded) Transistors for
every order over $10; This month only! Take advantage
of this free offer now! Don't delay! Top quality, silicon
power transistors 2N3055-1-10 for $5. I.C. sockets
(top quality) 8 pin-35c, 14 pin-40c. 16 pin-45c
Copper clad board— fantastic value: 6Vj" x 5"— 4 for
$1 80, 9" x 12"-$ 1 75. HA1322, 5.5 watts Peak
Power I C. incl. Cct diagram $1 .75 ea or 4 for $6 CMOS
I.C.s: 4000. 4001, 4002. 4007-35c ea 4011.
401 2— 40c ea , 4006-$2 50. 4009-$ 1 20. 74C
Series: 74C00-40c, 74C02-45c Linear I.C.s-555
Timer (mDIP) — 60c, 741 Op Amp (mDIP)— 40c.
LM301. LM307 (mDIP)— 70c ea LM 709(DIP)— 75c
723 (DP)— $1. 3900 (DIP) $1 25, CA3012. CA3013.
CA3018 (Can) — 80c ea Semiconductors —
BC547.BC548.BC549 — 10 for $1 50. BC557.
BC558. BC559— 10 for $1.50 BF198— 5 for $2 BF
185-3 for $2, BC635- 4 'or $2. OA90-10 for $1
EM404— 10 for $ 1 . EM 410— 10 for $ 1 .10. 2N6 107-4
for $ 2. 40250 (2N3054)-3 for $2.50.
2SA353(AF1 26)— 5 for $2, C106D S.C.R (400v 4A)— 3
for $3.50 Resistors, Carbon Film, ’/zwatt. 5% in El 2
values, Range 10 ohm to 1 Meg -All 3c ea Polyester
Greencaps. All 10%, 100v Rating 001 001 5. 0022.
0033 0039. 0047. .0056. .0068. .0082. 01— 10c
ea 015. 022— 1 2c ea.. .033. .039. 047-I4oea .
.056. .068. 082 — 17c ea 0 1— 20c. 15 — 23c.
.22— 26c For more super bargains in Electrolytics.
Switches. Panel Meters. Super Bargain Packs, look up
other Advertisements in this issue Post and Pack 60c or
extra for larger«parcels.
MICRONICS
P.0. Box 175. Randwick. 2031
N0MI5
" The Sound People
MICROPHONE
> STANDS
V SERIES 900
903
Floor
Satin and bright chrome durable finish Based on proven
field designs from NOMIS. one of Australia s oldest
sound specialists Professional quality at surprisingly
low prices. \
NOMIS ELECTRONICS PTY. LTD.
689 SOUTH ROAD.
BLACK FOREST. S A. (08) 293 4896
And these Suppliers
N S W. Martin de Launay. S y d n e y - 2 9 5 8 34
Newcastle-2 4741 Wagga-21 4644. Wollongong- 28 6020
QLD Martin de launay Brisbane— 52 8467 S.A. N*' duller.
Adelaide- 74 1 162 Mt Gambier SES8 Services-25 5970
W A. Atkins Carlyle Perth-22 0191 N.T. Veneman & Wyatt
Darwin— 8 1 3491 VIC. JES Electronic Components.
Melbourne— 88 5282.
emcD
DE LUXE PRECISION
MINIATURE MACHINE SHOP
_ _ an efficient universal machine equipped with:
3 jaw Lathe chuck, 3 jaw Drill chuck. Set of 8 Milling and Drilling Tools,
Grinding wheel Guard and 3 wheels, set of 6 Lathe Tools, Live centre
and DeLuxe Instruction Book . . . and it will do the following jobs.
BASIC UNIT:
70mm swing,
170mm between centres.
OPTIONAL:
THREAD CUTTING
GEAR CUTTING
FRET SAWING
JIG SAWING
CIRCULAR SAWING
SPINDLE MOULDING
PLANING
SANDING AND
POLISHING
FLEXIBLE SHAFT
ELECTRONICS Australia, December, 1976 135
R.F.2266B
l
STRIPS Iran mt '
FLECTROUIBE as
Electrolube Contact Cleaning Strips
are manufactured from specially
developed card impregnated with an
Electrolube Contact Lubricant.
They have been designed for cleaning
and treating small relay and non¬
wiping contacts where only
a very thin film of
Electrolube Contact
EtnmihlO Lubricant is required
II UllUlu ■ • • E G- Intercommuni-
Phnntnno cation- Telecommuni-:
ullUIJ hi h cation and Computer
, Systems.
Available from leading
electrical wholesalers.
Information on ELECTROLUBE CONTACT CLEANING STRIPS and other
ELECTROLUBE products is available from Australian agents:
/B* RICHARD FOOT (AUSTRALIA) PTY. LTD.
VEA 63 HUME STREET, CROWS NEST, N.S.W. 2065. Telephone: 43-0326:
IN STOCK NOW!
IBETA 23-Channel AM Mobile
Citizensband Transceiver
OUR PRICE
$89
+ P&P $5.00
(NORMALLY $139.00)
J SPECIFICATIONS
1 . Semiconductors: 1 9 Transistors and 1 5 Diodes
2. Frequency Range: 26. 965MHz-27. 255MHz
3. Mode of Operation: AM
4. Controls: Volume Control with Power On-Off Switch • Variable RF Gain Con¬
trol • Variable Squelch Control • Delta Tune Switch • Channel Selector Switch
• CB-PA Switch • ANL Switch
5. Connectors and Jacks: Microphone Connector • Coaxial Type Antenna Con¬
nector • Public Address Speaker Jack 3.5mm • External Speaker Jack 3.5mm
6. Speaker: 3 Vi inches, 8 ohms
7. Microphone: pynamic Microphone (500 ohms)
8. Power Supply: 1 3.8 VDC Positive or Negative Ground
Cali, write or phone to: C. H. S. TAYLOR'S WAREHOUSE SALES
1 69 JOHNSTON STREET, COLLINGWOOD. VIC. 3066 PHONE: 41 9 3862
SUBSCRIPTION SERVICE
Subscription Rates
$A 14.00 per year
within Australia.
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Name . .
Address
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Postcode . Enclosed is
for .
years
Advertising Index
A.W.A. Marconi School of Wireless
120
ACE Radio
130
Aegis Pty. Ltd.
102
Akai Electric Co. ,
6
Adcola Products Pty Ltd
' 26
Audio Engineers Pty. Ltd.
10
Audio Telex Communications Pty. Ltd.
63
Aust. Consumer Assoc.
67
Australian Time Equipment Pty. Ltd.
108
Auriema (A'asia) Pty. Ltd. 36,101, facing 36,101
Bail Electronics Services
106,1 16,124
British Merchandising Pty. Ltd.
69,112
Bright Star Crystals Pty. Ltd.
100
BKX Electronics Supply Service
128
Cema (Distributors) Pty. Ltd
34
Channel 2 Wollongong
122
CRC Chemicals
61
Classic Radio
94,102
Clock Disposal.Co.
134
Convoy International Pty. Ltd.
facing 37
Cunningham R.H. Pty. Ltd.
47,123
Danish Hi-Fi
5
Deitch Bros
132
Dick Smith Electronics Group 42,80,81,82,120
Dynetics Pty. Ltd
77
E.D. & E. (Sales) Pty. Ltd.
72
Educal Kits
51
Electrocraft Pty. Ltd.
74
Electronics Australia (Year Book)
26
Electronic Concepts Pty. Ltd.
98
Electronic Development & Sales Pty. Ltd.
117
Elmeasco Instruments Pty. Ltd.
56
Elliott Machine Tools
135
Ferguson Transformers Pty. Ltd
119
George Hawthorn Electronics
103
Kit Craft
134
Haco Distributing Agencies
facing 100
Hagemeyer (Aust)
OBC.IBC
Harman Australia Pty. Ltd
8
International Correspondence Schools
116
Interson Pty. Ltd.
35
Jacoby Mitchell
122
Lafayette Electronics
79
Lanthur Electronics
112,133
Leroya Industries Pty. Ltd.
7,15
Linear Electronics
134
Micronics 85,119,120
.131,133,135
Namco Electronics
88
Nomis Electronics 97,116,120,135
OBC Imports Pty. Ltd.
18
Paramount Rentals Pty. Ltd.
96
Peter Shalley
68
Philips Industries
12
Photimport
4,22
R.D. Electronics
93
RCS Radio
122
Radio Despatch Service
131
Radio Parts Group
2
Richard Foot (Australia) Pty. Ltd.
136
Royston Electronics k
133
Sabtronics International
84
Sheen Electronics Aust
64
Scope Laboratories
28,29
Sontron Instruments
77
Sony Kemtron Pty. Ltd.
IFC, 1 6
Stanton Magnetics
24
Star Delta Co. Pty. Ltd.
119
Stotts Magna Sighter
108
Stotts Technical College
118
Sungravure Pty. Ltd.
1 10.1 1 1
Swan Electronics Pty. Ltd.
121
Tandy International Electronics
50
C.H.S. Taylor's Warehouse Sales
136
Technical Book & Magazine Co. Pty. Ltd.
113
University Graham Instruments Pty. Ltd.
58
Vicom International
124
Video Hi-Fi Centre
122
Warburton Franki Heathkit Centre
39
Warburton Franki (Sanwa)
44
Willis Trading Co. Pty. Ltd.
106,124
Wireless Institute of Australia
127
Zephyr Products
74
136
ELECTRONICS Australia, December, 1976
WHY YOUR NEXT CASSETTE
SHOULO BE A MAXELL UD
3 THE SHELL — Even the best tape
can get mangled in a poorly
constructed shell. That’s why
Maxell protects its tape with a
precisely constructed shell, made of
lasting heavy-duty plastic.
No fixed guide posts are used. Instead
Maxell uses nylon rollers on
stainless steel pins thus elimi¬
nating the major cause of
skipping, jumping and
unwinding.
A tough teflon (not waxed paper)
slip sheet keeps the tape pack tight
and flat. No more bent or nicked tape to
ruin your recording.
Maxell doesn't use a
welded seal, but puts the
cassette together with pre¬
cision screws. Result —
Maxell doesn’t jam.
ULTRA- DYNAMIC
1THE RESEARCH — More than
twenty years ago, Maxell produced
their first reel of magnetic tape. At
that time, Maxell made a com¬
mitment to produce and sell only the finest
magnetic products their technology could
create.
That commitment still stands today.
THE TAPE — This continuous .
research has lead to the develop¬
ment of the Maxell UD (ultra
dynamic) cassette. A tape that has
a coating of super-fine PX gamma ferric
oxide particles with an extra smooth
mirror-finish surface.
All of this adds up to high output, low
noise, distortion free performance and a
dynamic range Equaling that of open reel
tapes.
4 THE LEADER — A leader tape
that has a four function purpose,
a) Non-abrasive head cleaning
leader (cleans recording head
for 5 secs.).
b) 5 second cueing line (recording
function starts 5 seconds after the line
appears).
c) Arrows indicating direction of tape
travel.
d) A/B side mark (indicates which side is
ready for play).
© ©
Now you know why your next cassette
should be a Maxell UD (ultra dynamic).
maxell.
The sound expert's cassette. UD available in C60. C90 and Cl 20
Distributed by Hagemeyer (Australasia) B.V. Branches in all States
WT GD 127M
Ibr what you are
about to receiye.
innovations inside, all models reflect the best in modern design combined with control
layouts to give you an ease of operation you’ve never experienced before. Best of all,
each lives up to our firm policy of Original Sound Realism.
Features JVC-JRS600 FM/AM TUNER (illustrated) With 5-way SEA: tape dubbing:
hi and low filters: THD 0.1%: FM noise reduction circuit: 110 watts minimum per
channel RMS: FM sensitivity, 1.7uV: signal to noise ratio, 65dB (Stereo): AM
suppression, 55dB: stereo separation, lKHz-50dB: alternate channel selectivity, 80dB.
Others in the JR-S range: JR-S400 — 70 watts per channel RMS minimum.
JR-S300 — 50 watts per channel RMS minimum. JR-S200 — 35 watts per channel
RMS minimum. JR-S100 — 20 watts per channel RMS minimum.
the right choice
For details on JVC Hi Fi Equipment, write to: JVC Advisory Service, EO. Box 49, Kensington. N.S.W. 2033.
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